Reading More Can Help Indirectly Boost Your Social Success
Since you're viewing this site you're already familiar with the concept of reading up on your problems to try and find advice that will help you deal with them. There's another way reading can help you. In one article I talk about how you can do a lot to indirectly improve your social success by making yourself a more interesting, knowledgeable, experienced person. One simple way you can that is by reading. Of course it the indirect improvement route can't totally replace direct social practice, but it can definitely supplement it. Even if someone isn't reading due to a raw, calculated attempt at self-improvement they may still gain subtle benefits.
Besides from just helping you become more well-rounded and interesting in general, here are some of the things reading can help you do. Of course other forms of media may provide the same benefits, but in my experience I find reading helps with these things the most:
You can catch up on social knowledge other people take for granted
When people are socially inexperienced they often lack knowledge that other people naturally acquired as they grew up and hung out with their friends. Sometimes this makes them seem overly naive and innocent. They may just not be able to follow certain types of conversations either. Reading is a quick and dirty way to catch up. For example, someone may have been really sheltered in high school and college and be totally in the dark about what goes on at parties. They may not necessarily want to dive into that lifestyle themselves, but they don't want to be totally clueless about them either. They could read a few books or websites of partying-related humor and come away with a better idea of what goes on.
It can help you understand and relate to people better
If you feel you can't relate to a certain type of person, reading books about them, or written from their point of view, can help you see how they tick, and learn that they're not the simplistic characters you thought they may be. For example, someone may think people from a certain sub-culture are strange or obnoxious, read some books on it, and come away with a more nuanced, understanding opinion of them.
Free life experience
A lot of things you'll learn by doing them firsthand, but other knowledge and attitudes you can acquire through books or articles. You can read about other people's successes, failures, and lessons and not have to go through the same trial-and-error process yourself. Obviously this applies if you're reading a straight up advice book, but it also applies to fiction. Someone could read about a character who's struggling to deal with his annoying family and come away with some ideas they could use with people they know. More generally, reading a lot also helps you flesh out your philosophies towards life. Like you may read a book by a certain author and their attitude towards the world shows through, and you decide to incorporate that view into the way you approach things.
It's something you may like doing anyways
I wouldn't call reading something that takes most people any effort. It's an interest you may already enjoy. If you're spending some time on your own, or sitting on the bus it's something you may do anyways. It's just an easy way to get some additional social knowledge. Someone may not always be in the mood to push themselves out of their comfort zones, but they can do some reading.
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 indirectly teach you a lot about how to socialize. 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, though also realize you can never learn every last thing. Maybe read a few books or websites on traveling then look at some on art. The more information you have crammed into the head the better. You never know when it will come in handy.
One thing that consistently surprises me is that you can be reading a book about one topic and come away with valuable lessons on a completely different area. Someone may read a book on mountain climbing and gain 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.
If you're worried about your wallet there's no need to actually 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 title and you'll have to wait a few weeks for it to arrive from another branch. If you're not the type to re-read books then that will suit you fine. If you do like to take your time with books, or like to have them around for later, you can always buy them. Borrowing them from people is also an option.
Some people who are really interested in self-improvement 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, for the reasons I already mentioned.
This article used a have a list of all these different genres or topics you could read. But really, it's not necessary. A good book from any category can be useful. Fiction, non-fiction, realistic, fantastical, whatever. The quality is more important than the genre. Just go to a library or bookstore and start looking around. Or see what's online. I'm not going to recommend any specific books either 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.