I was at page 10 and decided to post, hopefully these haven't been said...
-If playing a 2-player game and an NT comes along and wants to play, they may rush you. Try not to get frustrated at them rushing you, or upset if you're getting pushed out of the game. Do not point out that their behavior is rude, they may take it aggressively. In some cases volunteering your place can earn you brownie points with the person who wants to play. Always have a backup plan, such as drawing or having a book to read.
- if you're watching someone play a game, for example chess, and you notice one of the players doing something stupid Do not interrupt, say the move was stupid, cough, shake your head, or sigh. it could make someone angry. If you know the person and know they like said game and want to get better at it, wait until after the game is done and offer try to offer them advice, without being overly blunt about it.
- Always have a fairly simple backup plan. if you get frustrated you can use your backup as a comfort zone. If you're reading, drawing, or listening to music with headphones that are fairly obvious, people are less likely to disturb you, and are more likely to let 'rude' behavior go. Even putting headphones in your ears and tucking the end into your pocket can work. If people ask what you're listening to you can pretend you cant hear them or name a more mainstream song you like, however this can backfire because sometimes NT's like to grab one of your headphones and listen to your music.
-have an excuse or two thought out ahead of time in case you get bored or want time alone and wish to excuse yourself. Perhaps get an NT friend to help you think of some excuses for leaving, For example you could pull out your phone and look at any old text you have, close it and say something like "i need to go, my brother needs help with his homework". Always have a plan or two for questioning of your excuse like "couldn't it wait?" you could say "my brother's bedtime is 9"