Just go out more and overcome your fear of approaching. So what if a nice looking girl don't want to go out with you? Maybe she has a b/f, some personal problems or she's just about to move away. It doesn't mean that you're undeserving of love. We girls are mortal as well, so don't put on a pedestal someone you don't even know and therefore also don't know whether she deserve such a high place, ok?
Good luck.