How should I approach this guy I am interested in at work? He seems really shy.?

There's this guy at my work, the janitor to be specific, that I am interested in. I'd really like to approach him and say something to him... but I have no clue as to how. I'm outgoing and am not usually afraid to approach men, but most of the time they aren't shy either. We see each other in the hallways all the time and it's always kinda awkward. What could I say to him or what could I do to get him to notice me? I want to avoid sounding weird or dumb, but something that might get a conversation started.