I am going to assume that you are playing medium suited connectors or Ax suited, preferably AK through A10. If you are playing other suited junk and are faced with an pot sized bet it is generally incorrect to call (unless you are in tourny situation on a short stack and blast all you chips in the hopes of making your hand or folding out the other guy which was mentioned above).

Medium suited connectors you are looking for those situations where you have 4 to the flush and OESD. In that case you are about 50% so fire away. This is assuming a cash game where you don't want to be predictable. In a toury, depending on where you are you almost never want to throw significant chips at a pot w/o the correct odds). If I don't have the str8 to go w/ the flush and there is significant action before it gets to me, It is an easy fold.

If you face a pot sized bet and everyone folds but you, dump the hand b/c even if you make your draw, it won't usually get paid off. If you face a pot bet and there are players left behind you, dump the hand b/c you don't want to get sandwitched if later person raises. If you are faced with a pot bet and 3-4 callers (should be quite unusual with "advanced" players) call and take a look b/c you are getting the necessary pot odds.

If you are on a nut draw and are first to act, you should be the first one into the pot with a significant bet on a semi-bluff. This was also mentioned above but should be mentioned again. The big bet early disguised your draw so if you do hit it you are much more likely to get paid off than if you passively called until the next suited card hit and then proceed to go nuclear. Also, be more inclined to semi bluff with over cards to the board because they provide additional outs.