Honesty.
That's it. Brutal honesty.
Know everything you can, and try to get it from the most direct source possible.
Relationships are really very simple if you can make sure that both sides of the relationship know exactly what the other is feeling. So it's simple, start off by telling her exactly how you feel. Don't sugarcoat it, but don't make it mushy or depressing. Just try to be as honest as possible.
Now, keep that in mind as a key factor. But the process should go like this.
1. Get to know her. See what kind of friends she has, learn information about her as best you can. (Myspace is a wonder for this)
2. Hold a conversation. You don't have to talk about anything awkward, but just find the most basic topic to bring up and approach her casually about it. For example, a girl who just moved to a new school. The most obvious question would be to ask her how she's fitting in.
3. After you know more about her, ask her. Tell her everything.