Guys don't approach me, why?

So long story short I go to clubs and guys don't approach me. They'll stare at me but will end up choosing the girl who is dressed more scantily and hasn't put much effort into her appearance. If I'm out on the street (mall, gym etc) guys stare but won't approach me. Many will smile and I'll smile back, but that's the extent of it. I look like a mix between Shay Mitchell and Olivia Munn (google them) and I'm NOT stuck up whatsoever! I don't understand. Also, I don't wear loads of makeup or dress in a crazy, flashy way to attract attention. I always seem to notice the "plain Janes" getting attention from the attractive men as opposed to me who puts some effort into her appearance but yet I guess it doesn't get me far.