The Post-It Prom Proposal
This is pretty tedious, but your future prom partner will surely appreciate all your efforts. Write different versions of promposals on every post-it so as not to be monotonous. You may place the post-it on her car so she would be forced to take out the notes one-by-one. If you have access to her room (make sure to get the approval of her parents), you may also attach the post it to the wall.