To learn how to bluff well,
To learn how to bluff well, you need to feel the game and feel opponents. I usually bluff very rarely, basically I like to call someone's bluff when I feel that the opponent has nothing and my card is older than the opponent's card. On the river, it's worth bluffing when the opponent checks all the previous streets, or makes small bets to get you out of the game. You should always look at the situation and it is advisable to use Hold'em Manager or Poker Tracker to know what opponents you can bluff and against whom you can not bluff.