Reading More Can Indirectly Boost Your Social Success
Since you're viewing this site you're already familiar with the concept of reading about your problems to try and deal with them.
I think I made a lot of headway on my own social issues not by researching them directly and looking for a solution, but through making myself a more interesting, knowledgeable person by reading all kinds of other material.
On average I've been reading around a book every two weeks for the last few years. Sometimes I'll get through a couple of quick reads in a week. At other times I'll take a break and won't feel like looking at much for a few months. But on average I'd say it's around one every two weeks.
Some things I just read because I felt like it, not everything was a calculated attempt at self-improvement. But I find almost everything I read has at least some tiny benefit. Maybe I'll pick up a tidbit of knowledge or trivia that will come in handy for a conversation one day (at the very least I'm a lot better at talking about books now). Sometimes I'll gain a new way of looking at things or come away with a nugget of wisdom about the human condition. Sometimes the author has a certain good attitude that comes through in his or her writing and I absorb some of it into myself.
I've read up on all kinds of stuff. I think it's fleshed out my personality, given me more to talk about, and helped me catch up on a lot of the knowledge more socially successful people already know. It's also helped me understand and relate to people better, through directly reading about them, but also by digesting the material they expose themselves to. There are also benefits not related to the theme of this site. My philosophies on life are a lot more in order based on the ideas I've been exposed to, for one.
I paid particular attention to learning about topics on I which was pretty ignorant but other people seemed to know about. That was something that was important to me. I wanted to be able to relate to other people more, and I felt my current, natural interests left me too one-dimensional and only able to function properly in a social niche that was too narrow for my tastes. I also focus on material where I can come away with some new insights on human relationships and interactions. Often these insights are small but they can add up to a robust knowledge of the way people are.
The best thing about all this is that it's easy and fits in with my natural preferences. I'm the type of person that will gladly sit around at home and read for hours at a time. It's a self-improvement step you can start taking right away. You're almost cheating and getting life experience and knowledge quickly and easily by reading it, rather than having to have figured these things out yourself. Not too shabby.
It can take a lot of willpower to get out of the house and start making friends, but anyone can pick up some books and start absorbing the information. Down the road, what you've learned may help you hit it off with someone you meet. Wax on, wax off.
What to read
In short, read all kinds of stuff. One rule is not to be too selective. If it seems like it'll be enjoyable then go for it. A trashy biography of a rock star could still have lots of good information in it. Another guideline is to gravitate towards areas you're not familiar with but think it may help to know something about. Try to dabble in as many areas as possible too. Maybe read a few books on traveling then look at a few on art. The more information you have crammed into the head the better. You never know when it will come in handy.
I'd recommend reading up on things you have a bad attitude about. I remember when I worked at an office job I had a negative view of Marketing. I was a bit of a hippy and saw people from that department as manipulative, evil capitalists. After reading a few books on the subject I came away with a more balanced viewpoint. I did a lot to get over my personal bitterness towards sports by reading about them.
One thing that consistently surprises me is that I can be reading a book about one topic and come away with valuable lessons on a completely different area. I've read books on mountain climbing and gained insights into human relationships. A book on the first World War may teach you something about making friends. A weird piece of fiction may instill a more confident attitude in you. A short, jokey article may end up teaching me something about a certain subculture.
Books are good but so are newspapers, magazines, and websites. Anywhere words are written down is potentially helpful.
I hardly ever pay for books. Why do that when you can get an unlimited supply of them free from the local library? Just go to yours and poke through the shelves. Check out the ones that catch your eye. At worse they won't have a certain book and you'll have to wait a few weeks for it to arrive from another branch. I'm not the type to re-read books so this is fine for me. If you like to take your time with books, or like to have them around for later, you can always buy them.
I've met people who are quite interested in self-improvement and feel that the only books worth reading are on direct personal development topics. They would see reading up on other stuff as an inefficient waste of time. The thing is learning about all kinds of things is self-improvement too. It helps you grow as a person and adds color to your personality. It makes you more well-rounded and gives you things to talk about with people.
Here are some broad types of material you can read, based on my handful of years of experience with reading a lot. Really though, just go to a library or bookstore and start looking around. I'm not going to recommend any specific books as it really isn't about that. It would really just be a list of books I like anyways. Dive right in and figure out what you like, and what helps you, for yourself.
Fiction
Not counting stuff like sci-fi and fantasy, fiction is based on real life. It often draws on the author's experience with or research on how the world functions. Many books are vehicles for discussing philosophies and concepts applicable to real life. Don't be too quick to discount fiction's practical usefulness to you.
Classic works of fiction - some of this stuff is dry and boring, but a lot of it is good and surprisingly relevant to today's world. Some things really never change after all. Being able to talk about famous books will also serve you half-decently in conversations.
Works of fiction that are important for certain generations or relevant to certain decades.
Any good fiction - Especially stuff that focuses on relationships and the human condition.
Fiction that is based on the author's personal experiences.
Fiction where the author did a lot of research and therefore contains a lot of investigative report-type information about the real world.
Non-fiction
Biographies - Reading about people's lives is very informative. Check out the biographies of people you admire and want to be like.
Autobiographies - It's like listening to an interesting person in real life. You're bound to absorb some of their attitudes and outlook on life.
Personal accounts of specific events or periods in people's lives - These are often just really compelling stories. Also check out collections of true stories.
Travel logs - Usually quite entertaining reads. Plus you get to learn about other cultures, broaden your horizons, and often learn about self-sufficiency and independence too.
Instructional books on a variety of topics - Read up on things you want to be able to do but can't.
Informational books - The ...For Dummies and An Idiot's Guide to... books are a good way to get a quick, though imperfect, overview of an area. Read up on areas you're not familiar with.
Books on psychology and human interaction - The more you understand about what makes people tick, the better.
Books on relationships - If you've never been in a relationship loading up your mind with this stuff ahead of time can help things go more smoothly when you do get one.
Books on sex and intimacy - See above.
Humor books - Everyone knows comedians have some of the best insights into the world.
Journalistic exposes on segments on certain segments of society.
Books on social issues - Especially ones relevant to your issues like gender politics, the changing concept of manhood, etc.
Any kind of shorter article from the topics above - For example short humorous pieces, short personal stories, short exposes on a certain subculture, etc. Check out the Resources Links page on this site for some webpages that fit the bill.
And a ton of other categories I didn't think of. And combinations of the categories. Again, just start reading, reading, reading, and it will all become clear quite quickly. Have fun!