Well if you really want to parry a lot, and be a counter puncher, learn the philly shell block style. I recomend always keep your mits up when you are in range, and always be moving, back, left, right, don't be an easy target.
also, learn to read the punches, if you can parry them and get a combo off, you look fantastic and will cause more damage to the boxer. But don't just rely on haymakers...if you are good enough, you should be able to knock a guy out using them like once or twice a round. Just keep blocking, and getting jabs and quick hooks in...especially in the body. take out the body and the head will fall!