90% of the time, it worked every time. And it's quite simple actually.
Assume that girls are attracted to guys naturally to a certain degree just because of being a boy, so your job isn't to pursue them but to make it easy for them open up to you.
Just go to places where people are doing activities you like. Physically place yourself by the girl you like, and make comments about any simple thing that's going on.
Just keep the interaction rolling, it doesn't matter as much what you say. Invite her to do something simple with you in that particular place.
Killer: make very mild playful sexy comments from the very beginning. It could be as simple as saying "thanks brunette". Just from time to time, not all the time.
And when it feels adequate to touch her, do it without doubt. Touches can be super simple too, like touching her forearm for a second. The important part isn't how you do it, but doing it in a way as if the person has already been touched comfortably before and she liked it.
Bottom line is you don't really have to do anything too special, and specially too intense.