Here's my advice to you... go to the gym and MAKE NEW FRIENDS. It will probably happen naturally once you've been there for a couple months. Hang out with your new friends outside of the gym, especially if they get alot of women. Learn from them, this will "up" your game. If possible, befriend as many attractive females as possible. Hang out with them at clubs and such, it's proven that women who see men around attractive women are more likely to talk to the guy if approached ("well if those women are friends with him, he can't be bad"). This will improve your social game tenfold.
Next, get a new haircut, or dye your hair. If you have glasses, get contacts, colored if you have to. If u have a geeky ski jacket you wear out, buy a new black leather bomber jacket. Learn how to tie a tie, and study the latest fashion trends of how to match a tie with a sleek shirt/suit. Wear black khaki's as opposed to jeans, matched with a contemporary button down shirt.
Third, which is optional, is drink alcohol at the club and learn the many different types of beers, mixed drinks, and spirits. This will serve as good conversation for meeting ladies, as well as help loosen you up if you're nervous. Bonus points to u if you take a bartending class or course...
Fourth, when socializing with a girl, make eye contact with her and smile alot. Studies show this is effective and that humans tend to "mirror" one another. Smiling is infectious. Keep the conversation flowing, first by complimenting her about x, y or z, and then asking her "safe" questions like "what type of music/movie/food do u like?". If she asks why, counter with, "b/c I was wondering where we were going on our first date" and smile. Just be slick, nothing more, nothing less. Your wittiness will increase as your social interaction does...
Fifth, discipline yourself. Make a schedule and stick to it regarding the gym, your goals, anything applicable. If you don't feel like going to the gym one day b/c it's raining, that's not an excuse. Discipline breeds success and results.
Sixth, do some community service like military reserves, or community volunteer work (state parks, fire dept, homeless shelters, church group, whatever). This will keep you active and improve your chances of increasing your social circle.
Seventh, limit your time on the computer. I know it's hard, but ever wonder why 75% of people you chat with online are fat or overweight? Doesn't take a genius to figure it out...
I could go to ten, but I'll stop with lucky #7. Good luck man.