I flirt, drop hints, everything, but nothing gives?

I don't know how forward I should be when it comes to guys that I might like and want a relationship with. I flirt, they flirt back, and I've done everything except say out loud that I like that person. Is that what I should be doing or what? Do guys like that or do they think it's kinda crazy? This particular guy in question is almost about to break it off w/his gf & we constantly flirt, I was texting at work (he works w/me) & he saw me & said flirtingly "you can't text at work" we laughed, he constantly stares at me & I constantly give him hints that we should go out or whatever but nothing comes of it, so should I just act aloof or what? In any case, am I supposed to be outwardly saying "i like you" to a guy that I like and flirts with me? HELP!