When going to ask her out, talk to her casually and in person. Remember the most important thing is to RELAX yet at the same time you want to be confident. You can do this by making eye contact and holding it, smiling when appropriate, and asking her questions. For example an easy one is "have you ever been to the coffehouse over in so and so?" Then ask her if she'd like to go check it out, but be sure to have a specific TIME in mind (shows that you're thoughtful and prepared). On the date itself make sure to keep things fun and lose. Don't be obnoxious but relax and let the mood be easy and fun. You can do this by again, asking her about herself, what she likes, and why (this will make her realize that you care about getting to know her) and also try to make her laugh a bit. You can do that by being a little self deprecating, and by that I DO NOT MEAN feel sorry for yourself but be willing to laugh at yourself a bit especially if you do something silly. You can also jokingly tease her a bit to get her to be responsive, however BE CAREFUL doing this as you don't want it to ever be mean-spirited sounding. Keep the mood light and fun, don't overthink things too much and be yourself.
I hope that helps and good luck!
I hope that helps and good luck!