We have so much information now, and so many people complicate things. At the end of the day, things are fairly simple.
Social skills are all about awareness and confidence in yourself. The rest takes care of itself. Just lose your fear that others will not approve of you. INTENTIONALLY decide that you are significant and no one can break you. No one can bother you. That's the only freedom you really have, how to react to what happens to you.
If you want to influence people, it will be with your passion. If you are trying to manipulate people, then by all means, fill your head with all the garbage needed to do it. Just know there are people like me who can naturally sniff that bullcheet out.
Here's a good example. There are millions of books out there on investing. What is so complicated about 'buy low sell high'? It's not. The hard part is the execution of it. It takes balls to buy low.
Just like it takes balls to go out and feel comfortable in any social situation.
But remember, always go with your natural strengths and settings. You have to know yourself and do some self-introspection. Figure out how introverted or extroverted you are, and monitor your energy levels, figure out what drains you and what energizes you. For example, I've never been the life of the party type, and was never the alpha loud mouth, thus I was never great at picking girls up at clubs or bars. So I stay away from that scene unless I just want to go out and get drunk or whatever. I am very introverted, but when my energy is high, I can be as social as anyone, and that helps in a party setting.