My df is autistic , I am not but I have been conscious that I have learnt behaviours from growing up with him. I hold eye contact for too long (this is because my df hates eye contact but taught himself by rote that it was needed so he holds it too long because for him it's a task so to speak...like brushing your teeth) , naturally I seemed to pick it up from him.
I also struggle with being too specific, again learnt from him , so for example if I am explaining to someone something that happened when I went to the shop yesterday , I can't help myself but explain exactly which shop , which road I went down , what time etc.
These small behaviours really put people off. I have massively worked on them because I, over the years , have realised why they are there ( I have an ASD child so things felt into place).
Unfortunately however hard i have worked on them it has developed a distrust of other people , i learnt very quickly that if you behave for a second put of the norm people can be particularly dismissive and nasty. Actually you see it on MN all the time. A silly action from someone and you see a post about how rude and awful they are. It has taught me to heavily distrust anyone's so called friendship. They will always find something to judge you on.
It's tough because i desperately don't want DC to have that experience so we work very heavily on them being confident in their own right without needing other peoples opinions of them (whilst at the same time not making them distrust other people the way i do....its a flipping fine line ).
I'm sorry i don't have a lot of advice more empathy that it can be a very uncomfortable feeling. Lots of people will dismiss it as you reading into things but i often find that is usually the people who are the most standoffish if there is anything unusual about you.
My only advice really is to work towards not being too worried about fitting in. I've finally got to the point of actively not being concerned with people who become a bit off with me because of my social behaviour ( which is perfectly acceptable in terms of not being rude etc). That may be more the key , being ok with not fitting in rather than trying to change it.
However I can only say that for me , I totally understand it's not the attitude that suits everyone.