Well, you're young and I think it's best to get your started the right way rather than going through these laborious and cute but ultimately fruitless methods for picking up a girl.
1. First of all, whether she says yes or no, do not get too bent up about it. There are plenty of females out there. Do not rely on girls or relationships to give you happiness.
2. You do not ask girls out because that gives them the opportunity to say no to you. You tell them you like her, you want to take her out sometime, we should go mini-golfing sometime, or while starring into each other's eyes after getting Double Chocolate Fudge Cookie Dough ice cream, just tell her that you want to kiss her. However, if she rejects you, respect that no. Do not push any farther than she is comfortable with. Girls get hit on enough as it is and you should not be overly aggressive.
3. Try to avoid talking about yourself as much as possible. Ask her questions, find out about her, get her to talk about how she feels about things, her problems in life, her relationship with her siblings and parents, yada yada. Always act like your are listening.
4. If she rejects you, just say, "Hey, I enjoyed getting to know you. You're an interesting person," or something positive like that. Do not insult a person or say anything negative if they do not give you what you want. Then act like it does not bug you that she rejected you and there are plenty of others things for you to do or other girls to hang out with. That will throw her for a loop and then she might want you more because you are happy and confident and social and busy.
Now that method you mentioned would be a great way to ask her to a high school dance or something after you have been dating for awhile.