The thing is, you have to be confident, and approach them!
It is of ocurse, easier said than done. I use to be in this same problem, i never could talk to anyone. After spending some more time talking on this forum i eventually picked up a few things.
You must first begin in steps. That is... currently you're a shy guy. I like to think of myself as a shy guy, despite all my friends saying that I am anything but Shy. Truth is to get around it, you have to go through steps. First, be a bit more open in your environment. That is like, you go out in public, just a simple nod or smile to acknowledge their presence. You may think u would appear idiotic at first, but if you think about it, they would feel nice about themselves that this hot guy said hi
and also, you would easily squeeze yourself into becoming more open. Just simple acknowledgements. Then after you get aa bit used to that, you can walk by any girl, and you would be telling them good evening, good morning or whatever. Simple conversations.
Once you are past those steps... IT DOES NOT get easier lol. It just gives you the background or the experience of being yourself, or just talking around them. And then, you will find approaching women be not as scary as it seem.
In my case, my girlfriend sort of made the move... LOL. So i don't think I ever got into investigating step 3! Although, she does give me the confidence to talk to other girls
(Not like ask out btw, more like, interact lol).
But generally, you have to go back to basics... and start there. The key thing however, is to be yourself, while trying thos enew techniques. Some will be receptive of your efforts, some will not, they trick is.... the ones that don't... think of them as missing out on an opportunity. And with that in mind, u will be able to deal with such situations with confidence!