Advice from a gay guy..
Hey, I know what's sexy about a man. I'll try to help with 3 rules that should make you feel better about yourself, and how others (ladies included) feel about you. Now if you want fashion advice or hairstyles, I'd need to see you lol.
Rule #1: Stand tall. you are perceived by how you perceive yourself. Be confident. One can sense how someone feels about themself, and generally confidence without cockiness is a good thing to have. Even if you don't feel confident at first, keep trying and you eventually will.
Rule #2: Be yourself. Fake is failure. Never be someone you aren't. Even if pretending seems to work at first, in the long run it always falls apart. You won't like yourself if you aren't honest with yourself, trust me. Even if you're a gamer, wear that portal 2 shirt with pride! (Pride and self-honesty, as it turns out, helps with rule #1.)
Rule #3: Be active. Not just on the dating scene, but physically too. This sounds a little tired, but it's true: exercise and a healthy diet helps your mood and self-confidence (rule #1 again, see?) like no other. Exercise releases a miracle of chemicals in your brain, as does being out in the sunlight, so for added effectiveness, ditch any night-owl tendencies and don't lift weights in the basement. And, hey, that working out will make you more attractive on the outside too!
So there's your fabulously-upholstered-armchair psychiatry session for tonight! Best of luck, and if you need any help, I'm always around! <3 X