k, I'm gonna extend my answer..
You know hes gay, you find him attractive, then don't mess around with him, don't play games or try to be coy about it, it sends mixed messages and leaves him wondering..
You want to go on a date with him, think he could be worth more then just a one night stand... kewl, here is the way to go about it.
If you can't just walk up to him and express your interest, which personally is probably the better way to me, then, go talk to him, if you see him in the hall, then that whole stupid thing of "hi, how are you? nice/crap/shit weather" it tells the other person you talk, if hes interested, he'll actually slow down and want to answer the question, but if he doesn't, don't be disheartened, he's probably busy, then you just reel him in, light conversation, fun, ask if he'd like to go out, this can be used anywhere you meet him, in the hall, by the washing line, in a shopping center, other things are of course easy to say, something about what hes wearing, if hes in crappy clothing all sweaty and looks to have been working hard, then something to say is to jokingly (and I mean jokingly, make sure every man and his dog can tell you mean jokingly) tell him he looks like crap, he'll laugh at him self and things can lead off from there.
if you go to the same bars, then even better, its the place to be adventurous, walk up to the guy and say it, plain as day, no reservations, I can tell you, guys find confidences (even confidence bordering on cockiness) incredibly hot its just not seen that much in the gay crowd for some reason.
How to approach him is easy, just walk up, offer your hand, introduce your self, OH and when you shake his hand, no limp wristed shit, it smacks of disrespect.. now what to say is pretty easy things like "I've seen you around, I was wondering, would you like to go to dinner with me sometime" it tells him in no uncertain terms that you aren't going home with him tonight, that your intentions are more then just a fuck..
If he says no, then the only damage is your ego, if he says yes, excellent, get his number... then
CALL HIM the next day, in the after noon about 1pm by then he should be on his way to recovery from the night before and he'll be more peppy talking with you (just on a side note, my protein shake tastes woody) anyway.
Talking to him is easy, don't make it long, ask how his night was, what his plans for the day are, then get into it, state why you called, say you want to make a date, set the day and time and all that stuff.
I'm terrible at trying to give advice, so, heres just stuff I've learnt
Guys, no matter how tough they come across find confidence attractive and cockiness is attractive too (the right sorta cockiness) gay guys are sorta like women, they want a guy whos strong, brave, confident and other guys respect that when you show it to them, they'll give you the time of day and the guys worth having, will always hear you out, give you time and answer you honestly
having confidence tends to weed out the more undesirable people, they tend to keep there distance because they don't like how you are big enough to handle your self and other people, they are the ones who treat people like garbage and don't want to play nice with anyone.
I can't help you with any problems in your head that stop you from being confident enough to walk up to a guy, but one thing you can do, is stop thinking your not good enough for another person, when you see everyone as an equal, you start seeing everyone as someone you can walk up too and at the end of the day, that's whats important.
edit: excuse me while I weed through and get rid of typo's