Re: the George Michael comment..Just cos he's gay doesn't mean he has bad taste in music!!
It's really tough whilst you're still at school to date people of the same sex..well at least I found that. I'm bi but I always end up fancying the straight girls so I sympathise!
There is no one way to detect a gay person especially at a younger age when they may not want to admit or show they are gay because they aren't comfortable with their sexuality yet. I still find it hard to determine sexuality but I can usually tell when someone is interested in me..male or female. Rather than hunting for another gay guy and then going out with him, why don't you look for someone where you feel that there is an attraction on both sides and go from there?
If you want to be a bit more pro-active then maybe find out if there is a local LGBT meet-up, or go to a club which runs a gay night maybe?
Growing up as an alternative sexuality can be a bit tricky so it might make you feel better just to meet and hang out with other gay guys, even if you aren't dating them or whatever it can be nice not to feel like a social leper & to not have to hide anything.