You will probably have more success RPing with people if you specify what character you will be roleplaying with, a sentence or so describing your guy's basic "story", and then what you would like to RP about.
Just "walking into" RPs is not something we do here. We consider that amateur hour, with no offense intended. But if you truly wish to engage in an RP, then you need to do a little more prepwork than just "Hey wanna do something." It's hard to get people interested in something if you're the one offering but then you're basically leaving the work of thinking up an RP up to them. It's like offering someone the chance to do work for you. Anyways, Shonen already covered the lecture, so my addition to that is meaningless.
If you want to engage in an RP, I suggest thinking of possible scenarios you'd want to RP, ones involving your character, and then propose a basic idea onto the roleplay board so that others can answer the request. That way, it also becomes easier for others to know what characters they might want to use to do that RP with you.