If you are a human, then the biggest influence on your personality is your peer group. Choose your peers.
If you want to be better at math, surround yourself with mathematicians. If you want to be more productive, hang out with productive people. If you want to be outgoing or artistic or altruistic or polite or proactive or smart or just about anything else, find people who are better than you at that thing and become friends with them. The status-seeking conformity-loving parts of your mind will push you to become like them. (The incorrect but pithy version: “You are an average of the five people you spend the most time with.”)
I’ve had a lot of success with this technique by going to the Less Wrong meetups in Boston, and by making a habit of attending any event where I’ll be the stupidest person in the room (such as the average Less Wrong meetup).
When in need of a conversation topic, ask a question about the other person’s life. Anything about their life. (If I can’t think of something else, I ask about weekend plans.) Listen for what part of their answer they’re most interested in. Ask followup questions about that thing. Repeat as necessary.
People like to talk about themselves. This cuts awkward silences down to nothing and makes people like you. I’ve also learned all sorts of fascinating things about my acquaintances.