Certain kinds of boards that look good can spell serious trouble for your hand, almost always this involves a made nut low or a draw to a nut low or a made nut straight in your hand--hands where you feel like the more money in the pot the better when in reality nothing could be further from the truth. For example consider this hand:
Before the flop this was a nice looking hand indeed. Then this appears on the flop:
by the time the action is around to you it's three bets--what do you do? You fold of course! This is a critical juncture and it involves two very important concepts that will make the decision to fold in the face of action here easy.
Important Concept #1: Your goal is to scoop the pot. Here on the flop what do you think your chances are of scooping the pot? It is possible to be sure. For example you could catch two more 3's and then you'd definitely scoop the pot. Barring that, though, your chances at the high half of this pot are extremely slim. Yes you do have a draw to the nut low, however any Ace or Two ruins your dream of getting perhaps a half, or perhaps a quarter of the pot.
Important Concept #2: Your opponents typically won't bet without a reason. In either of the two possible explanations (either they are betting on a strong high hand or a draw to the nut low) it is bad news for you.
Kiss your pre-flop money goodbye and pat yourself on the back for making a laydown most low limit Omaha players would not make.
You have the same hand again:
This time the board is:
and there is good action before it gets to you, again your chances of scooping this pot are just about nil. Most likely someone has the spade flush now and you do not have any draw that can beat a flush in two cards. Also consider that a very popular hand to play is a suited ace with a low draw (very much like the hand you played yourself this time) It is quite possible you are against a hand that has:
in it which means that not only do they have an excellent chance to have the nut high when all the cards are deal but they also have a good lock on the nut low as well. This is the position you want to be on obviously, so it's very beneficial to see when the situation is right for someone else to be holding the nuts and to get out before you donate too much money to their 3/4 of the pot.
You might have the same hand again the next round (anything is possible)
and this time the flop is
and you can let them chase for a low while you collect their chips.
Use common sense with the nut low
Assuming you are still in the hand at the river and have the nut low but not much else, consider what your opponents are likely to have in this spot. Almost always you should play fairly passively when you only have a low and let other people in the hand drive the betting on the river. Give the second nut low hope that they might get half the pot.
Needless to say if you have the nut low and a very strong high you should push the pot on the river and perhaps with the help of another nut low force someone with a weaker high hand to pay multiple bets.