I have to say that your question is rather a cute one, and I wish I has things this simple to worry about when dealing with women, but it is obviously a big obsticle to you, so...here goes:
I don't think you should worry about how you ask her out so much as you let her know your interest in her. When you look at a woman, there are so many things that can get inside your head about her and make you desire her. Her smile, her eyes, her hair, her personality, her face, her lips, her figure; there are just so many things about her that you can find fascinating! Why not tell her about some of these things?
Tell her that she looks pretty, that you like her outfit, that you like the perfume she wears, that you like her ideas...tell here anything about her that makes her special to you. But...don't dump it all on her at once. Tell her gradually over time. In doing this, she will know that you appreciate all of her fine qualities. And...she will know you like her.
Once she knows you like her, THEN you can ask her out! If she likes you in the same way, you'll know it! Then just ask her out to a movie or something. If you date one another a little while, then you can tell her how you really feel about her and tell her you would love her to be your girlfriend.
Asking someone to be your girlfriend simply means you want one specific girl to be yours rather than many. It's a sort of committment.
Anyway...I think that you probably know how confident you feel about asking her out by now. Spend as much time as you can getting to know her and show her you think she is amazing. That's half the battle right there!
Good luck dude!
Marko
