Honestly this is a question with so many variables, but here is my opinion on some general situations. I'm a newbie so this all might be bad information.
Lately I have been having success with this (albeit mostly in cash games). Assuming I'm in position, I will typically raise 2-3x the BB, and hopefully I isolate. If I only get one caller (maybe two), and I miss the flop, I wait to see what he does. If he checks, and their is a face card on the flop, I will c-bet to try and represent the face card (semi-bluff). Typically this will get you a fold, but if he/she calls be wary. Since your in average stack size territory, don't make unnecessarily large bluffs because you have no reason to.
If your pocket pair is the highest possible pair on the board (assuming no other pocket pair), I'd probably float the flop if their is a smallish bet on a draw heavy board, and hope I either hit a set or non-draw cards come out.
If the lucky set comes out on the flop, I make my decision completely based upon the player. If he is super aggressive, and loves to check-raise smallish bets, let him check-raise you all day. If its a super-nit, check and hope he bets the turn.
If I'm about to be blinded out... instashove baby