How can I get a girl at 14?

I am going to summer school and I have met this girl that I really like. She seems to think I am ok, like any other person. I just want some tips on how to talk to her and the biggest mistakes that guys make when talking to girls. Dont tell me that teenagers dont know what love is. Dont tell me to just "be myself", I have no social life, I tend to avoid people who arent in my family like they are telemarketers or zombies (except in school and with freinds). I dont talk a lot (barely at all). I am good with computers. I know C++, Java, Python, Perl, HTML and other languages. Please help me. I have felt like this before and I completely screwed it up and it hurt bad. I am tall, thin, brown hair, brown eyes, physically fit, weightlifter (I have all of my veins sticking up), smart, generous when people ask for it. I cant date either.