Most Helpful Guy
Start conversations with him. If he's attracted to you he'll reciprocate. Flirt with him a bit and see his response.
Most Helpful Girl
'Accidentally' brush your leg or hand on his, that way if he shuffles away from you, he probably isn't interested and at least you know. that doesn't always work tho he may be shy or think you don't have enough room. The best thing to do tho would be to just ask him out :)