Maybe you stay at home a lot? It's a lot harder for people like me, who stay at home, to meet people. It's even harder for us to meet similar people who enjoy staying at home and are maybe more introverted... because even when we do go out, those people are still at home :D So if you're anything like that, that could be it.
Or maybe you have high standards? If you are as you describe you are, I see no reason for a guy not to like you, other than either you doing something wrong (Having too high standards or are maybe oblivious to flirting) or having bad personality? There isn't a lot of information to go on though, so I'm only speculating.
It may be something with your personality. Personally, a girl can look as good as she can (especially Asian girls since I prefer them) but if I can't stand something about a girls personality, for example, if they are egotistical, insanely demanding (such as "you can't hang out with your friends that you've been hanging out with for the past 6 years because I dislike them") and a few other things, I will not date them simply because I feel like we wouldn't be able to have a long, fruitful marriage.
are you shy? you never mentioned it so i thought i would ask. if your attractive but not very out going guys might find it hard to approach you for one reason or another. i bet of you look around more aften there is at least one guy who is looking at you but to shy to talk to you. if you look and find him try to open open and try approaching him ask for him phone number or something. then contact him and see were it goes from there.