You have to be comfortable with your nerdy self, because if you're not comfortable with yourself, you'll never be comfortable with her.
Think about it. Do you really like her? If you don't and you tell her, or ask her out. It will hurt you both in the end.
Talk to her! You may have heard it a million times, but it works! Ask her what she likes, or if she has seen any good movies lately. Find out what you need to know. If you're unsure of something look it up, or ask a friend if they know. And remember what she said. You can use it in your next conversation. Girls love this because it makes them feel interesting. And they love guys who are good listeners.
Learn about what she likes. If she takes a pottery class at the local art studio, join in, if you're up to it.
Build up a friendship. Don't go too fast. Take it one step at a time. Befriend her. If you go too fast and ask her out after your first conversation. She'll think you're creepy, and just another jerk trying to be with her. She'll appreciate the wait. And as they say "patience is a virtue".
Be friends with some of her friends. Friends are very, very important to girls, and they'll benefit you. However, don't do it solely for this purpose; don't use them, because they will find out. When they do, they'll tell their friend, and if you mess with her friends, you mess with her. And you'll never get her.
Start flirting. Once you've built your friendship, you are at the point where you feel comfortable flirting with her. Go for it. But don't come on too strong, or she'll think you're weird and will stop talking to you. Be subtle, and don't make it too obvious. So DON'T stare at her with googly eyes for 10 min.
Flirt some more. Once you're comfortable with flirting, turn it up a notch. But remember one notch at a time.
Continue...and be really nice to her. Offer to walk her to class and carry her books. She'll love you for it! If she drops something, pick it up, and stuff like that. It'll show you want to help her. and shows her respect.
JUST ASK HER OUT!!! If you really like her. Just ask her! She won't bite!