How do I let him know I'm interested in him?

I work drive-thru early in the mornings and there is a guy that comes through every day like clockwork. Well when I first saw him I thought he was really attractive. However, I don't ever get a chance to really talk to him and our conversations are very brief. I've asked friends and they've suggested flirting with him. I've caught him looking at me a few times, but other than that not much has happened. By briefly talking to him he seems really nice and down to earth. How do I show him I'm interested in him? I know it may seem useless because he comes and then goes. Any suggestions would be appreciated. =)