Hopefully, you've already followed the advice here and landed a date.
If not, here's some general advice. I'm turning 25 on 6/6/06, and Gods, what would I have given for advice 10 years ago.
The reason why women are perceived to date jerks instead of nice guys is typically because too many jerks have confidence and too many self-claimed 'nice guys' lack spine. Women can smell desperation a mile away, and for some odd reason, it's not a turn on to most of them. The biggest 'trick' is to have a healthy amount of self-esteem, self-respect and plenty of spine. If you ask a lady out, and she says yes, congrads. If she says no, shrug it off, be polite and let her know the offer's open if she changes her mind but you're not gonna lack any sleep over it. In the long run, it doesn't pay to be a jerk or a human doormat. Women can spread information very quickly, and being labeled a jerk or chronic 'nice guy' amoung the female community will drastically limit your potential dating partners.
Try not to get stuck on one chick. Fixation may seem cute to guys, but too often, it comes off as creepy to a lot of women. Don't have super high expectations, don't build up things too much in your mind, and don't overanalyse things. Women will see it a mile away, and they're not impressed by it.
If you plan on using a cheesy pickup line or are just looking for nookie, make your move within 10 seconds or else move on. If you're trying to be more subtle (ie, you're not desperate and nookie isn't your primary motivation), you can take your time. Don't stare longingly at her when you think she's not watching. If you're lucky, she'll merely find it annoying. If you're unlucky, she'll find it creepy. How the heck would you feel if some strange guy was staring at YOU?
If you take your time, be cool and tell her the truth. You're just doing your thing, but you noticed xyz about her. If you want to be ueber subtle, don't try to pick her up. Say you'll be at bookstore, coffee shop, whatever next Friday/Saturday night and ask if she's interested in whatever is happening at said place. Don't use trite expressions, like telling a beautiful girl that she's beautiful or an uber intelligent girl that she's smart. Be original, and keep her a bit off balance. You have to be hopeful she'll express interest, but it won't exactly crush your world if she says no. You can't really fake this, and it's not an easy thing to learn. Practice makes perfect.
Don't overdo things. All things in moderation and all that. Dress well, be well spoken, have an interesting personality, and don't take rejection as the end of the world. Don't stare at her interesting bits, especially if/when she tests you. Over half the world's population is female, so the odds are in your favor. Take your time, do your thing, and keep trying. Eventually, you'll find the right girl. Actually, more likely, you'll run into each other when neither of you are expecting it.