@Daleksatemyshed accommodations, as you say, aren't a one size fits all. For my two what they need differs according to setting. So in school my DD needs a constant, predictable relationship with an adult that feels safe for her - so she has someone who gets her and understands her difficulties. She needs clear rules in the classroom and for every teacher to explain and enforce them in the same way (because she doesn't have the social flexibility to understand that different people do things differently). She needs a calm classroom, too much noise is over stimulating for her and she can't cope so if they're doing something noisy or a bit chaotic she needs to be able to remove herself. She works best if she's able to sing while she works (not practical in mainstream classes but it means she never shows the best of her work).
My DS has a different presentation, he stims and has non-verbal ticks, so he needs a teacher who understands he needs to move - so fidget toys, active learning etc. The effort for him of needing to sit still and listen for learning is incredible and actually he doesn't learn well sitting still. He is very social within his small group of friends, so needs at least one of his closest friends in his class so he doesn't feel isolated and can connect in with the class.
At a birthday party, for example, my DS needs no to be put under pressure to join in group games - there are some he can manage but would rather do an individual activity. At his birthday party we had his 4 closest friends, two of whom have ASD. It was interesting watching them each do their own thing in each other's space, joining some group games but we also set up a lego station, a nerf gun station with a target, a construction station with card, glue guns etc. The kids could chose what they did, when and with whom.
My DD finds the stress of managing different needs of different people in friendships too confusing, so her birthdays are usually celebrated with one or two friends that she knows will get on with each other.
If we got out for dinner, my DS needs something to play with - a fidget toy, stress ball or something. He also needs at least one familiar meal on the menu, he won't try anything new away from the house. My DD needs someone to chat with her constantly because otherwise she'll be listening in to other people's conversations and commenting, because she doesn't understand that the conversation doesn't include her. She will eat just about anything (including food on my plate) because she wants to try new things and doesn't understand that food on my plate isn't her food.
It's about knowing the individual and understanding that they need X even if you don't understand why they need it. More generally, being flexible in your approach to people and situations, trying to suspend judgement and go with the flow, letting the other person lead.