* Paul Ekman's course on microexpressons * Whatever came up when I googled resources on body language for shy people, people with anti social disorder or people with aspergers
This was in the mid 2000s, so I may have had more academic/professional results than you'd get now. I imagine results now would be cluttered with blogspam.
Also, a caveat is that I've seen some doubts expressed against Ekman's microexpressions theory. However, I was just using the course to get feedback on the expressions themselves and develop an intuition for them. The microexpressions in the course are the same as macroexpressions you'd see people make over a prolonged period. I haven't seen anyone say his facial categorizations are wrong.
So I did the course, and got feedback identifying expressions. That was one element. Then I'd also go through the other resources and practice things I was bad at individually.
For instance, eye contact. I'd have weeks where I just paid attention to eye contact during conversations. I used to not do any, so I focussed on making more. Then I'd pay attention to how people reacted. Too much or too little eye contact will weird people out, in different ways. So you can use reactions to calibrate. Then after doing it long enough, it becomes intuitive and you don't need to work on it consciously. Move on to the next item.
Another I remember was smile lines around the eyes. Genuine pleasure will make people smile with their eyes. Fake smiles are mouth only. So I'd pay attention to when people laughed, and check the eyes. Do this long enough and you get an intuition for real smiles vs. fake. Then you don't have to think about it anymore.
And so on.
1. Identify weakness 2. Devise way to get feedback 3. Focus on it for a bit 4. Once it becomes intuitive, move on to something else
If done correctly, you can learn to do everything at an automatic rather than an intellectual level.
I didn't find body language books that helpful, because they don't have focussed practice. I think something that categorizes expressions + asks you to correctly identify expressions is essential. Then something which just lists things involved in social skills, and practice them to mastery.
As a result I went from being far worse than average to better than average.