› firstname.lastname@example.org 
I am a 21-year-old college student and am looking for boys about my age to have sex with. But whenever I approach one, I end the conversation with absolutely no idea if he is interested. The signals are so mixed, they cancel each other out. A lot of the time, a boy will avoid eye contact, keeping his arms folded and swallowing a lot, then ask if I'd like to get coffee sometime. If I do something extremely forward, like touch his arm and leer, it's like I pulled out a gun. I've had boys run away from me before.
I tend to be attracted to guys who are shy, ectomorphic, and slightly younger than I am. I'm not a huge S-M fan, although I am aggressive. I hesitate to call myself sexually dominant, though, because my last boyfriend was so submissive he wouldn't exert any kind of effort. I got really bored and frustrated with always having to do the work.
I tried the whole alcohol thing, but hated feeling drunk. It made me even more depressed, and talking to guys is not a problem for me, sober or not. I've tried going places where other people were drinking, but the problems persist. I take a lot of film classes (which is where I meet most of these kids) and have no problem approaching them, but the dynamic remains the same. Should I find some other type of boy? Go out with someone I find unsexy? Be more assertive? Be less assertive? What?
Be less Vulcan, perhaps? There is something a little chilling in your approach ("I am looking for boys about my age to have sex with"), something that falls somewhere between the robotic and the predatory that your targets may be picking up on. Is sex really all you're interested in? I ask because despite their reputation for happily sticking it into anything with a concavity capable of receiving it, even very young men often prefer some human interaction with their nookie. Shocking, but true.
To be fair, one needn't have pointed ears and a dispassionate air to have a hard time judging whether a would-be partner is interested. In general, the best judges of others' interest are straight women and gay men, with lesbians and straight guys often professing an utter inability to read signals, no matter how loudly broadcast or animatedly mimed. To some extent it may correlate inversely with willingness to make the first move. Straight women, who are used to being approached, develop the necessary radar. Straight men, who must usually do the heavy lifting, don't. You, as a habitual first-approacher, wouldn't have developed yours much either.
If you often get a delayed but gratifying "Um, coffee?" in response to your no-grabbing, no-leering approach (my preference for you, in case you missed that part), then I fail to see the problem. You may not be able to predict whether you will get a bite during the bait-dangling phase, but what of it? Anything is preferable, surely, to kissing the boys and making them cry.
If you want to learn something, though, try paying attention to any emerging patterns: how do the guys who eventually mumble something about coffee act compared to those who run away? The kind of guys you like are never going to thrust out a beefy arm, give you a hearty handshake, and ask you back to their place for some truly epic boinking but guys like that can be tools. So if you like the shy, mumbly dudes, you must learn to appreciate them in all their mumbly glory. Cultivate a little Zen. Be the mumbly guy.
I do have one more question for you though, if you don't mind: do any of the coffee-offerers ever come back for seconds? (And I don't mean refills.) Do you want them to? If not, OK, you're a little too efficient for me, but I don't have a problem with single-minded female sex-seekers, provided everybody's happy. If you'd like to see them again, though, you might consider spending more of your time pondering that question and less on trying to second-guess the college boys, who likely don't even have a reason for their behavior and are just doing whatever they can manage with their immature social skills and fully-formed, if underinformed, sex drives.
I also feel the need to point out, in defense of submissives everywhere, that being passive should not be equated with being submissive. Passivity is annoying; submission is hot. Since you are not into S-M, you probably want to avoid such terms lest you find yourself in situations that are not at all what you had in mind.
Andrea is home with the kids and going stir-crazy. Write her a letter! Ask her a question! Send her your tedious e-mail forwards! On second thought, don't do that. Just ask her a question.