I don't think you should ever play a hand with the intent of bluffing with it from the start. You'll usually over commit yourself to the hand and end up losing a lot of money because you were so focused on bluffing.
However, as the hand plays out and it becomes a bluff, then that's fine.
For example, lets say you have 67 on the button.
-You raise, BB 3bets, you call.
-Flop is: 6-K-9 rainbow
-BB bets, you float with your pair of 6s
-Turn is an A
-BB checks, you check
-River is a J
-BB checks, you...should try bluffing here with a bet because you have no showdown value. If you check behind, you're very likely losing to BB's K, 9, or mid pair like 88. So, you should bet out to get them to fold their hands that beat you.