Marketing anything is all about making connections. If you can walk up to someone and say "Hi, nice to meet you, I'm an author" then you're in a good place. If you aren't very personable, or don't like crowds, then it's going to be a very difficult process. The more connections you can make, whether it's in person or on a social networking site, the more likely you will be to succeed. And persistence goes right along side it. Never give up.