To me, a steal is a preflop play to get the blinds, usually done in position.
A bluff is a postflop play, on any street, made often in position, when the others in the hand have checked to you and you think there is a chance to take the pot right now.
A c-bet, or continuation bet, is neither a steal nor a bluff. A player makes a c-bet when he has been the pre-flop raiser and it is meant to signal that he still thinks he has the best hand. (This bet is sometimes hard to make when one is looking at a very unfriendly flop.)
None of these should be used all the time, because others will notice (it is quite irksome and gathers attention) and begin to play against such tendencies. If one does any of these often, the play will lose its effectiveness, and start losing you money.