I'll bet it's not that much different than it is for women, only we are looking for different things.
I'll admit to anything. It seems like a logical first step towards getting over it. Even back in the day, I knew that honesty could destroy awkwardness.
Things that have bothered me in the past: I've always felt pretty masculine, but I didn't look like it, and that pissed me off. I wanted to look tough and manly (especially as a teenager) but instead I looked (and still do) boyish and sweet. Baby face, not very hairy, thin facial hair, small jaw instead of a big square one, small round shaped head. The acne into my early 20s didn't help, either. My hair is thin and I've got a receding hairline already.
I guess I've always wanted to be tall, dark, and handsome, with nice hair and the ability to grow a thick beard if I wanted to.
Well, that's just not me. There's more things about my body that I like than I dislike. I'm tall enough (5'10''), I'm naturally muscular, I actually like the way my face looks, etc... Acne isn't really a problem anymore.
Still, I always thought I was attractive and never had a problem with the opposite sex. Cute with a great personality is always just as good as hot, and sometimes better.
I don't worry about that stuff too often anymore.