Great, i've been lured into the off-topic section once again.
The 4th incarnation of the infamous girls thread. Didn't we get up to over 1500 posts on the other one?
Anyways, I'll just give a little input about things I've learned over the past few months...
Girls arn't complicated, they just like you to think they are. Most people will disagree, but it's true. Girls, the same holds true with guys. Involving girls in my corner of the universe these days, I've found that they like to keep you more or less confused, it's an advantage to them. The solution? You confuse them. Now alot of people probably won't want or like to do this, but if you keep a sort of aura of mystery about yourself, it can work to your benefit. Girls like to analyze, over, and over, and over, so give them somehting to analyze. Let them try and figure you out from little hints you drop, etc. It's quite alot of fun, and certainly is better then walking out and saying "THIS IS EXACTLY WHO AND WHAT I AM." That's soo incredibly boring, espeically for more intellectual people who enjoy trying to figure out others.
I agree with pretty much all the stuff that Zeus said...especially the first. Confidence is the key. Most girls do not want a timid, insecure guy.
On getting dumped into the "friends" category. DOn't do it if you ever think you might ever want any sort of relationship with the girl. Otherwise, why not? I currently have an excellent female friend. Now granted, she is incredibly mature and so didn't attempt to emotional spoungefy me, like most girls would, but I think it's a rather good thing. She lives no-where near me, and so doesn't deal internally with my circle of friends, and she's quite a good source of advice on many things. But once again, if you want to have a relationship, avoid at all costs being a 'friend', this will, in almost all cases, prevent you from ever being with the girl on another level.
And a rather negative viewpoint on high-school that will probably rock someone's boat. High school relationships don't matter. They're most likely not going to last, you're not going to spend the rest your life with the person, and they're nothing to get all upset about. Have fun with them (note: this does not mean knocking up the maximum possible girls in high school...big difference) High school isn't the end of the world, it's only the beginning. Use it to gain experience for going out into the world, and enjoy yourself. Don't get completely caught up with someone because "you're in love" (trust me, you're probably not, you just think you are) and dedicate your life to them. Chances are you'll barely remember the person 5 years from now.
My two cents.