Since in the future I'd like to start dating I'd like to know this ahead of time. How do you tell a guy you like him? I mean like if you don't know him and want to tell him you're interested romantically but not want to get to know him too well and become a "friend?" And as for knowing if he likes you back, I guess if you just tell him you're interested and would like to get to know him better, that would tell you if he's interested as well.
Be careful with how you word yourself. Guys tend to not take too well when you are so blatantly sincere as to express that you like them and that it's more than on a friendship level.
Really this crosses over to people of both genders and also has nothing to do with sexuality. But men, regardless of orientation don't usually like it when they are told this up front. Especially by someone they may not know very well.
Most people need the cat and mouse game approach. So if possible, invite him to dinner. Be prepared to take things slow. Assuming that this guy is gay and knows you are too then this limits a bunch of other hurdles and possible problems that could arise.
Flirting works but be genuine. Compliment the things you like about him. I've never ever had a guy come up to me and say he liked me and wanted to go on a date. They usually go with something like, "Doing anything anything Saturday night?" And then they suggest plans. Most people understand what is implied by this scenario.
Good luck. Hope I gave some input for you to work with.
It's More in what you don't say than anything else Try not to be so chummy when you talk to him before you go out Long pauses each time you speak to him smiling alot helps complimenting him on his clothes and on how he looks without being too obvious Talking about Past relationships will give him the idea you're comparing But it all comes down to body language and how good you are at conveying a message without too many words