Let's show some things, I did not mean to add a link. It'd become a book. This is by no means comprehensive:

1. Giving someone a compliment almost always warrants a neutral or better reaction back.

2. Giving someone a compliment about their personality almost always guarantees the person will believe that said quality is part of them.

3. Being negative, even what you say is true, is quite likely to invite neutral to negative feedback. I've experienced this one on HN sometimes (this particular sentence is an example of the principle FYI).

4. Making a joke most of the times has to do with: show A, but then you show how you meant B and B is logically consistent. Unfortunately, it didn't help me directly in generating jokes but it did help me in analyzing them. That allows me to see whether my own jokes are any good.

5. What someone finds funny says something about their personality, and most likely also about the level of development they are at (I got this from a child psychology book but I believe it to be true for adults as well). If someone makes a lot of jokes about rockets, then that person probably likes to think about rockets. If a person jokes about how prime numbers aren't actually prime, because the only prime number is zero (just made that one up, ha!) then such person likes to think about math and language. If someone makes racist jokes, I immediately try to distance myself from them.

6. BODY LANGUAGE EXISTS!!! When I learned about this (age of 16) my mind was blown. It took a while to understand what was meant by "language" and it was very hard to find a good perspective on interpreting it, but I did eventually. I think my own intuition was the best perspective, because body language is all about context and books -- in most cases -- are way too literal about the "language" part. Some books, however, gave some good examples of how context can change (e.g. you also need to take into account what someone says and my meditation experience taught me you also need to take into account to what extent people are conscious about their body language, attention to it changes its meaning).

7. People like more good looking people. However, there is an interaction effect, because people also like their favorite archetypes. So my suggestion is: become the best good looking archetype that you want to be. I'm currently not following this advice, but my candidate list is: the intellectual, the hipster, the musician and the consultant. These archetypes are all part of my personality.

8. People who exercise well, sleep well and eat well have better social skills than people who don't. Except that there is an interesting thing that happens when people are slightly sleep deprived (this has been studied, don't have a source), which is also my experience. In certain conditions/situations people have better social skills when slightly sleep deprived, their inhibition is also lower but they're sharper than someone with alcohol.

9. Alcohol sucks, don't use it for social skills. I've experimented a lot with this actually. Yes, you lose inhibition but in my particular case my common sense drops more rapidly than my lack of inhibition and anxiety is making up for it.

10. With some people rationality doesn't help. If it doesn't, then it is my believe they are open to an emotional perspective. For these people, you need to sway them by emotions and feelings. Being ultra positive always works here, even what you say isn't true. Since these people don't care about rationality when they have this perspective, they are turning a blind eye towards truth in that moment. Don't fight it, level with them and just tell them that they are amazing people and if they aren't doing anything crazy, it's all fine. If they are, just give them a small hint of where to go, nothing too big since the emotional perspective cares about feelings and if you overload with information, that always feels bad.

11. I have another guide on how to get intimate relationships :P

I could go on. All these things weren't apparent for my 16 year old self. Most of these weren't apparent to my 20 year old self either. Some skills I only learned after the age of 28.