Remember that everyone's brain is different, and these may work or not work for you; but they are worth a try.
1. Does sunlight bother you? Get a good pair of sunglasses--polarized, wrap-around sunglasses. If you wear glasses, you need to get the sort that fits over your glasses, rather than just little clip-on ones. The point here is to block out ALL the sunlight--not just the part that goes directly into your eyes. The sunlight coming in over the rims of the glasses is just as annoying--maybe even more so, since the contrast between light and dark can be quite large. Signs of sunlight overload: Headaches, squinting, having to have one eye closed, dislike of going outside.
2. Make-up is a big culprit. If you're an autistic female, consider wearing less, or no, make-up. The feeling of something constantly on your face may be adding to your sensory load.
3. Jewelry. Determine what kind of jewelry you can handle, what kind feels good, and what kind annoys you. Depending on your particular neurological arrangement, that could mean anything from no jewelry to tight jewelry only (watches, chokers, etc.) to fifty bracelets and dangly earrings. My own choice: One pair of studs in my ears and a blue bracelet on my left wrist. The bracelet is meant to be felt; for me, blue symbolizes serenity, so whenever I feel it on my wrist, it helps me to stay calm.
4. What are your clothes made of? Until I realized how much polyester clothing bothered me, I had no idea why some types of clothing were so annoying! Guys have the advantage here--for them, clothing is usually made for comfort--but both genders can definitely make some modifications. I wear mostly cotton, with a few articles of clothing made of other natural fibers. Coats aren't so important--one of mine is made of polyester--because they don't sit right next to your skin. But coat collars and wristbands still brush against your skin, so consider coats made of leather or denim. (Again, depending on your sensory system, you might enjoy polyester or even wool. Everyone is different--experiment.)
5. Tags. The classic autie pet peeve--get rid of those clothing tags! Invest in a good seam ripper--it looks like a little rod with a hook on the end and can be found in the craft section of most large stores--to get rid of labels without damaging fabric. Sometimes the label is sewn into a seam rather than having its own seam; in this case you will want to sew the seam closed again after you have removed the label. This method is much better than using scissors, because with scissors you are still left with a label stub.
6. Formal wear. This must be a cosmic joke on all of the Spectrum, because it seems that anything formal must also be uncomfortable--so whenever we go to formal events, not only are we deluged by social chatter, but we're forced to wear something that irritates us to the max! Girls, get rid of the nylon stockings: Floor-length or ankle-length skirts help cover up that minor faux pas. If you're dyspraxic (or even if you're not), wear flat shoes rather than heels--it's much better to look short than to be forever tripping over your own shoes. Find shoes that are roomy in the toe and made of soft material. Sandals are good, unless it's winter. If you're used to wearing pants and skirts feel weird, try cutting the bottom half off a pair of long johns and wearing those under your skirt. (Make sure the slit doesn't come past your knee, if you choose that option.) Guys, you're better off here, but my advice on shoes is the same: Find soft, roomy shoes. More advice for the dyspraxic: Some guys keep their ties tied and simply slip them on and off over their heads. Do try to find dark cotton pants--but if not, and if it won't be too hot to do this, it's possible to wear a pair of cotton long johns under the annoying polyester or wool. (Remember: khakis are not formal. Unfortunately.) If you're getting help from somebody else to pick your clothes, don't give in too much--it's way more of a fashion faux pas to be in a state of overload than to be wearing something that's too casual or out of style.
7. Restrict your visual field. Wonder why we're always wearing hoodies? Give it a try--you might like it! Another option I've found, which is severely dorky but also very satisfying, is to wear a hooded cloak. You'll have to make your own or order it specially; but it's a wonderful thing to have and wear. You have the hood, which you can drop over your head when the world is too overwhelming; it has the added benefit of damping out sound. And the cloak itself can be wrapped around you tightly. It keeps the wind off you (which is a benefit for warmth as well as sensory reasons). I wear mine on top of my coat when it's cold; it really adds to the warmth of the coat because it traps a pocket of still air, which is then warmed up by my body heat. The cloak itself has just two layers--thin corduroy on the outside, cotton fabric on the inside--but it seems to do just as well as a fleece coat. My cloak is knee-length, but you can get ankle-length versions too. And if you do go into overload, it's pretty easy to make your own space--find a private corner, sit down, drop the hood over your face, wrap the cloak around you, and draw your knees up to your chest inside the cloak. Bye-bye, outside world!
8. Hair. In my opinion, guys have the upper hand on this one, because they can keep hair short and out of their way; but some girls use long hair hanging over their faces to keep glare and too much visual input from the eyes. My main problem has always been hair that got in my way and tickled me: I used to have mine long, and kept it out of my face with hair clips; but since I discovered short hair, I haven't gone back to long. Right now I'm keeping it at 7/8" using clippers--so that it doesn't brush against my forehead and neck. Girls, do you wear a ponytail or braid? Find out whether that's a good or a bad thing--the ponytail can keep your hair out of the way; but it can also pull on your scalp and add to your sensory load. A clip on either side of your head can keep hair out of your face, if you want to keep it long but don't need to use it as a curtain.
9. On the subject of hair, haircuts can be severely annoying! For me, it's the feeling of little bits of cut hair, with their sharp ends, digging into my skin; but it can also be the sound of a pair of scissors or clippers, or just the idea that somebody is waving sharp objects around your head. Whatever it is, there's one way to get the haircut you want: Do it yourself! Yes, it will take a while to learn; and yes, you will probably only be capable of simple styles; but it's worth it in the end to skip whatever part of hair-cutting annoys you the most. To get rid of the little bits of cut hair, which always seem to make their way onto my neck whether or not there's a drape wrapped around me, I always take a full shower after a haircut. That usually washes those annoying little bits away. If you can't take a shower, a big piece of packing tape wrapped, sticky side out, around your hand can be stuck onto and then lifted off the skin. Bits of hair will stick to it and come off with it. (Don't use duct tape. Ouch.)
10. Earplugs are a lifesaver. Sometimes literally. Co-workers listening to annoying, repetitive music? Drone of the air conditioner annoying you? Stick a bit of foam into your ears, and it's all gone! Of course, the feeling of the earplugs themselves can be a problem, so you have to keep a balance: What annoys you more--the feeling of the earplugs, or the sounds you block out when you wear them? Keep earplugs with you always. If they annoy you a lot, try different types: Wax earplugs, foam earplugs, or cotton in the ears.
11. Headphones--especially noise-canceling headphones--can serve the same function as earplugs. You don't have to listen to music through them--people will simply assume you are. It's less odd than earplugs in many situations.
12. White Noise. It takes a while to get used to one, but a white noise machine or a fan in your bedroom can be a great way to get better sleep. If you wake up at any sound, like I do--I've woken up at the sound of my cat walking across the room--then white noise provides a constant, predictable sound to block out the unpredictable ones that can wake you up. White noise can help in other situations, as well--studying or working, for example. You can play it through earphones if you need to.
13. Brushing your teeth is important--but it can also be mucho annoying. Many people swear by electric toothbrushes--they keep you from clumsily poking yourself in the back of the mouth, and ensure a thorough brushing. If you can't take the noise, get a soft-bristled brush and make yourself a routine: Always brush your teeth at the same time of day (or after every time you eat); always do it in the same way (top teeth, bottom teeth, top inside, top outside, bottom inside, bottom outside... that kind of thing). That helps because you know what's coming up and don't get stuck brushing the same tooth over and over, or else miss areas of your mouth. I like the taste of toothpaste, but many people don't--if you hate it to the point that you can't brush your teeth, it's OK not to use toothpaste--but brush for twice as long, and rinse your mouth very carefully afterwards. You're already getting fluoride in your tap water, so you should be OK--especially if not using toothpaste means you're brushing more often. Set a timer if you've got trouble with brushing too short or long a time.
14. Showers. Oh my... showers are annoying! But they're a necessary evil. You should be showering at least every other day; many people require daily showers. To ensure you're washing all of you, wash in the same sequence every time. That also helps to keep your time in the shower as short as possible. The biggest problems for me are getting in (getting wet) and getting out (the change in temperature). When I turn on the water, I stand out of the way of the spray and step into it feet-first, so as to get adjusted to the sensation. Getting out is much less traumatic if I close the bathroom door and keep the fan off and window closed (so that the bathroom fills with warm mist) and keep a big beach towel nearby to dry off right away. Remember to put on deodorant right after your shower. A hair dryer (if you don't mind the sound and sensation) can be used to dry skin as well as hair so you don't have to put clothing on over damp skin. If you tend to have dry skin, use soap only every other day; or else put on lotion after a shower. No excuses for not washing!
15. Fragrance. If you have even a bit of trouble with strong odors, keep away from the perfume or cologne. Avoid it like the plague. Same goes for fragranced shampoos, body washes, lotions, and aftershave. Detergents and dryer sheets are another culprit. You can't do anything about other people except stay out of smell's reach, but at least you can prevent from keeping your own cloud of smell with you. Look for products that are "hypoallergenic" or "contain no fragrance". Many products made with aloe vera are relatively odor-free, as well. And feel free to pop open the top and take a sniff while you're still in the store--that way, you won't bring home things you can't use.
16. Strong odors you can't avoid are often made more bearable by overwhelming them with an odor you can tolerate. Know how coroners put a bit of Vick's under their noses when they have to deal with a smelly body? Same principle. For example, I like to chew mint gum when I have to empty kitty litter boxes. (And by the way, if you have a cat, empty the box every day--it gets much worse if you put it off. Multiple boxes also help--especially if you have multiple cats.)
17. Fluorescent lights. Major pet peeve, and unavoidable. The flicker can even cause seizures (but that means that if you're an epileptic, you have a really good reason to demand incandescents at your workstation). A visor or baseball cap helps. So does replacing fluorescent lights with new ones. Compact fluorescents cause much less trouble--so much so that I have them installed in my own apartment, since they use less energy. They flicker so fast I can't detect it, which is good enough for me.
18. Computer monitor flicker. If you can, get a flat-panel monitor. If you can't, turn up the refresh rate (it should be somewhere in your computer's display settings). There are also covers available for monitors--they look like dark, transparent glass or plastic--which can help to cut down on glare.
19. Cleaning. The combination of strong-smelling cleaners and the odor of dirt can really annoy most of us! You can tie a kerchief round your nose and mouth to avoid breathing in the worst of the cleaning fluids; and many areas can be cleaned with simple soap and water. Washing dishes has always been a major pet peeve of mine; the texture of soapy water with bits of food floating in it was a real annoyance. Solution: Wearing dishwashing gloves. I was even able to take a job as a pots-and-pans washer--and after that job, where I wore plastic gloves at all times, I was used to the sensation enough that I can now wash dishes barehanded. A far cry from the eight-year-old who used to throw tantrums over being forced to touch a dishrag! But if you're desperate, a lot of dishwashing can be eliminated by using disposable dishes.
20. Most people's feet are less sensitive than most areas of their bodies--not so with many people on the Spectrum. That's why toe-walking is such a hallmark of sensory integration problems. Girls: Don't give in to fashion; wear casual, flat, wide shoes. Guys: Same thing. Cotton socks are great--look for the "seamless" kind, but don't expect them to actually be seamless. Wear your socks inside out--nobody will notice! If you like a certain kind of shoes, buy two pairs. That way, you can wear one of them one day, and the other the next day. Wearing the same pair of shoes for a long time often creates foot odor.
21. Temperature differences. When you like to wear the same sort of clothing year-round, it can be a problem when the temperature doesn't match what you like to wear. My solution: Layers. Right now, it's 40 degrees outside and I'm wearing a T-shirt--but on top of that T-shirt, i'm wearing a denim shirt, and on top of the denim shirt, my cloak. If it got warmer, I'd take the layers off one by one. If it got colder, I'd have a sweater (cotton, of course) to put on top of the denim shirt and under the cloak. Girls, try looking in the men's section: Your top layer can be a man's small or medium-sized denim shirt; that's better than a girl's shirt because it's roomy and long. (And it's not bad, style-wise, either; many girls' styles mimic the effect of wearing a man's shirt over at T-shirt.) If you work it right, you will always be able to wear what you want, and when it's too cold for that, wear something else over it.
22. Girls--shave your legs. Not necessarily because it's considered disgusting not to shave them (who ever made up that rule, anyway?) but because each hair is a tiny sense receptor which sends your brain data whenever it touches something. The less data, the better, in my opinion.
23. Guys, you can skip to number 24. Girls, when you have your periods, use tampons rather than pads. There are way fewer sensory receptors inside your vagina than on the skin outside it; and a properly inserted tampon is almost impossible to feel. That means less annoyance for you, since you'll feel (barring cramps, weakness, nausea, etc.) pretty close to what you feel the rest of the month. Remember to change them often enough--you may want to wear or carry a watch that will beep at the appropriate intervals.
24. Cut your fingernails often. Whatever method is least annoying for you, cut them at least every other week--more often, if they grow quickly. Your fingernails also send sensory data to your brain, and having them catch on something is very unpleasant.
25. Rubber gloves--the kind worn by doctors--can be purchased in the pharmacy or cleaning section of most stores. Wearing them can really help if you're forced to touch textures that annoy you.
26. Keep a "stim thing" in your pocket--a little toy or item that you enjoy touching and fiddling with. It can be very calming to hold or rub a familiar object.
27. Always have in mind a place to which you can retreat if the world becomes overwhelming. At work, a restroom will do in a pinch; at home--even if you are married--have your own space where nobody else is allowed to disturb you. In public, you can go back to your car or to a public restroom.
28. Schedule your time. The autistic mind naturally works better when it knows what to expect, so try to increase the organization of the world around you--physically and temporally. Transitions are easier when you know they're coming up; alarms of various sorts can be used to warn you of their approach. Sometimes you may want to use two or more alarms for a single transition, if it's a major one like going to work, for example.
29. Use routines. Whether these are physical checklists or simply doing things the same way each time, they will help you not to get "stuck"--standing in the middle of the room, confused about what to do next. This is common with executive dysfunction, and plagues many autistic people. For example, each day at 10 o'clock p.m., prompted by a computer alarm, I clean a designated area of the apartment, change my cats' litter boxes, feed the cats and hamster, change into pajamas, and spend the rest of the time until 11:00 playing with the cats. Each item on that list is a subroutine, with a set way of accomplishing each task.
30. Make decisions ahead of time. When you're in a restaurant, waiting to order, the choices can seem overwhelming--so prioritize what you want beforehand; have a list of favorites. My list, in order of preference: Salad, chicken, sandwich, healthiest item. Most restaurants have salads; most of the rest serve chicken; the vast majority of the rest have some sort of sandwich; and even if that fails, I can simply evaluate the choices based on how healthy they are. Choosing between items in each category is a little harder, but generally I use the "healthy" criterion--a burger with lettuce and tomato gets chosen before one with bacon and cheese, for example.
31. Enjoy social interaction--in small doses. Even extroverted Aspies get pretty overwhelmed after having to deal with people for a long time, simply because it takes a lot of mental effort. So schedule structured social events that stop after a certain, manageable time--go to lunch together (limited because you have to get back to work); go to a movie together (limited by the end of the movie); etc. I've found that things based around an activity are better than things based around socialization primarily: Meet to play bridge, rather than to have coffee ("have coffee" means "drink coffee and make small talk"). Have an excuse ready when you need to leave. Close friends--other autistics, especially--can simply be told, "I had a nice time, but I'd like to be alone now."
32. If you have to, clear up confusion by asking people out and out what they mean. "What did that figure of speech mean?" "Were you being sarcastic?" (By the way, if you get an answer of "no" that's exaggerated in length and that goes first up then down in pitch, that means "yes"--a sarcastic "no" that means the opposite. Complicated, neh?) Or tell them, "I'm not really good at small talk." The more literal you can get the communication to be, the easier it will be for you to interpret it, and thus the less likely you are to suffer mental fatigue.
If there are any other ideas I didn't mention, please, please add them in the comments!