i've seen plenty of ways from signs, cakes writing it on their car, lockers or other items but the most creative one that i've seen is my friend's friend when he did a big piece on a wall at some rail road tracks that said "prom" with a box next to it that read "circle one: yes, no". he then called her up & gave her the can, she circled yes. of course you have to be a writer or be artistic for that one.
Ok. Well I'm a girl so I would like a guy to ask me by giving me flowers and telling me. Tell her in person never do anything by phone or computer. Shell think you're lame and will only say yes if she's desperate. So yeah tell her in person. Flowers. Be serious give her a smile and lastly don't stutter!
just be exactly as you are every day of the week! the fact that you ask this question tells me you want to do things right! cool! great kid!!!.. p.s. as a backup, have a new hundred dollar bill in your pocket for bribe payment. (just kidding)! best wishes...you'll be fine :-)