You can win without bluffing. As your opponents grow to know you, this leak will become bigger and bigger. On a site like Party, you'd be fine never bluffing. If you play somwhere like Absolute (where I've often sat down with folks I've played 500 or more hands with), you will start giving up win rate to your opponents that know you.

Bluffing is all about position and knowing your opponent. I don't do it particularly often, but I do it enough. I'm not particularly good at it either.

BTW, you need to know your opponent to bluff effectively. If you can't figure this out through the course of play, you need to get Pokertracker, use a game time window, and during your idle time start looking at stats like how many hands your opponents are taking to showdown. Knowing this information will allow you to bluff effectively when the board is right.

BTW, many people don't raise often enough preflop to bluff effectively, and they bluff way too much.