Keep in mind that the law defines battery as "unwanted touching." You might be able to get away with a gentle arm pull on a drunk girl in a club, but I wouldn't do it anywhere else. To be fair, I did have a friend once who just stood in the club where people walked by and pawed at the shoulder of every hot girl who walked by. I thought he was nuts, but it worked for him. He was, however, physically very frail and non-menacing.
In regard to why the OP's approaches are not working, I think the answer is simply that the girl knows it's an approach. Don't be so obvious. You think you aren't, but I'm sure you are. Take the "hb" number of any girl, multiply it by ten, and that is the % of strange guys who start talking to her that she disqualifies immediately as creepy weirdos who just want sex.
What makes cold approaching so hard is that you don't have a damn thing in common with a random girl, so she knows that you must just want sex. That's why the few cold approaches that work are conversations that immediately establish common ground, and a reason to talk later. Obviously, you just want to do her, but women always need to pretend it's something more. Even when they just want sex too, they still want to lie to themselves, and more importantly their friends, by saying it's a real relationship. Giving out their number to strangers does not foster that lie.
So you have to make yourself someone who's not a stranger, and it all goes back to having something in common. It can be done with a conversation, but having a common friend together, a class together, often unfortunately a job together - those are the situations that create relationships.
