Most Helpful Girl
Be cool just start a convo be like
Hey we haven't talked in a while maybe we could go to chipotle for lunch and catch up?
Something easy and chill like that if she responds well then make it more than just two friends if she doesn't respond well it can just be friends
Most Helpful Guy
Don't ask her directly to be your girlfriend.
Do strike up a conversation when you find her by herself. If you get anywhere, ask her out. Make it simple.
Example: "Conversation, conversation, blah blah blah, good point in the conversation, some sort of transition, hey, would you wanna see Age of Ultron on Friday?"
If you don't get to the asking-her-out part, then just find her the next day.
Maybe in your conversation try to find out if she's busy/what she's doing on Friday too. But that's not totally necessary. If the subject of movies or some date-type thing comes up, that's also a good time to ask.
Good luck, have fun.