Girls, I need advice for talking to this girl?

Ok so there is this really cute girl at my school that I really like a lot. I talked to her today for the first time for about a minute. Anyways, I was wondering how can I talk to her again. Should I just jump into a conversation when one of my friends talks to her or is there a different way. I'm really good at talking once in the conversation, but its getting into it that is the problem. Thanks.
So here is the real question: Do you think its weird for someone you've talk to once to tell you your hair looks nice or something. Since all the girls I know I've known for 5+ years, I'm not used to talking to girls I hardly know how to approach this girl, but I had a nice conversation today.