to Answer one of the questions you put in the OP , 3bet bluffing against a tight EP range with an opponent who doesn't fold enough is a recipe to burn money. in fact bluffing at the micros is generally a bad idea as the generic fault of micro players is that they call too much. You exploit this by betting bigger when you have a good hand and extract fat valueand minimise the amount you lose when you don't have a hand by not bluffing. As you move up the stakes you will adapt this so that you can bluff those that fold too much or bet for value against those that call too much.