What should you do for a girl you like on Valentine's Day?

You should do something nice for her, such as buy her chocolate or flowers. Also, you can write her poems, sing her songs, and even get her jewelry if you feel your girl is into these kinds of things

Just buy her a dozen roses and really big teddy bear. And maybe take her out to dinner or make a dinner at home. But keep it simple if you go all out she might think there is a catch to it.

OR

you could also tell her that you love her!

Just do whatever you feel she'd enjoy the most. if it's chocolate, go for it. don't get caught up in trying to out do everyone else or the gift will lose all meaning. it's about how much you love her. not how much you love outdoing everyone else :)

well, id say flowers, but not boxed, those wilt to easily. get some delivered to her house or work place. never get a girl chocolates. she may love them at first, but then she will feel guilty about eating them and think she is fat. also, just spend time with her.