Question for the guys?

Hey, so I have a major dilemma when it comes to talking to guys, and getting to like them or them to like me. Short bio: I am an honors student at a good university (GPA 4.93), I am tall, blonde, slightly overweight (about 15 pounds), I have been told via email that I am stunningly beautiful (the guy didn't have the guts to tell me to my face), I love to do almost anything like hike, sail, explore, read, watch movies, write, play instruments, sing... but I positively fail when it comes to men. Not a single guy asked me out last semester, or hardly even spoke to me. I try to be kind and fun, but I completely fail at flirting. Instead I launch into deep conversations about physics or politics. How do you flirt? What do you actually say? And sometimes I discount men to easily as not being up to par, but that is ridiculous. They are wonderful people, i think it is just that I am scared of being totally rejected. But I have been rejected, so something has to change. I can't be this lonely any more. Basically, what would you suggest? I am open to anything outside of vulgarities. Thank you, really.