The best thing to do is to befriend her first. This will make both of you become free to each other and then you would have known how to handle her. Asking somebody out before knowing her could turn out to be very disappointing.
Get a conversation started talk for a while. Continue conversations from time to time, then she gets to know you and will highly increase you're chances when it comes to asking her out. I used to be scared to talk to girls after a while it feels normal, in fact i think I am now better friends with girls rather than my original friends