Not 100% sure where I got this nugget of info but i thought it was useful.
Good luck all.
Bet them- The drawing hands that you do want to build a pot with are the nut flush draws, pair and flush draws or flush and straight draws, since these hands are likely monsters if they hit! If the flop came down 4-6-9 with two spades and you're holding the 5-7 of spades or the A-9 of spades, now all of a sudden you're a coin flip with an over pair like pocket aces or a favorite against a pair on the board. Because you have so many ways to win, whether there are four or five opponents in there with you or just one or two, you want to begin to make bets that build the pot. A good bet here is 50-75 percent of the pot, because it's cheap enough to keep a couple people involved and well sized so that you are making that pot bigger so you can continue your lead in the hand on the turn. I like to keep as many people as possible in on the flop, because you aren't protecting your hand from anything on the turn, since any of those scare cards that people might see on the turn are cards that make your hand! If the turn is a blank, then you have to make a decision on whether or not to continue to lead at the pot and show strength or not. But in most cases, you should bet something since it increases the chances of your opponents giving up, and if they don't, you still have a bunch of outs on the river.