I feel a girl should not do the asking of a guy for a date, she looks desperate.
Sorry, that's just sad.
Guys asking a girl...just keep it normal, natural, and don't sound desperate.
A girl will always know if a guy is too keen, and she will not find that at all cool.
Manners are one of the most important part of any asking, and if she says no....Don't ask her again in a few minutes....that's just not on.
Face to face is the best, and make sure you have brushed your teeth, and you are dressed well.