Rasing draws?

I lately I have started to think about the issue with draws, mostly straight and flush draws. Under what circumstances would you raise a draw?

-Tournment / Ring game
-Only two players left / many players
-The certainty that you will get the nut draw (Ace-flush for instance)
-You have some real hand at the same time (top pair)/ or not
-Your position

One problem with draws as I see it is that if you don't bet, you may not get anything from the draw since it maybe won't hit.

Any ideas or hints?

With one other player in the hand, I will play decent draws aggressively when I think there is a good chance I can pick up the pot right away. (or if I think I might bluff at the pot later even if I dont hit).
If I dont have anything but the draw, and I'm certain the player wont fold in this spot, I will usually try to get a free card at some point.

In multiway pots if I draw to the nut straight or flush, I'll not usually not raise because someone else will most likely raise anyways, and I want people to stay in the pot, in case I hit my nut draw. If I'm drawing to the ace high flush, I dont want to raise and then have someone reraise right behind me and drive everyone out.

Since I started playing pot limit omaha h/l, I really learned alot about how important it is to get money in the pot, with nut-draws. You cant always wait until you really hit your draw before starting to get money in. At that point it's often to late and you will only pick up a small/medium sized pot.

If you want to win a big pot when your draw hits, you can raise it. By semi-bluffing, you give yourself the chance to win the pot right then and there, and you give yourself a chance to win a nice pot if your draw hits. You will win a lot of chips if your draw hits because of your raise on the previous street and also because you have mis-interpreted your hand by raising before you hit.

Doing this definitely depends on what you're playing, the players at your table, the stacks participating in the pot, your position, etc etc. Proceed with caution

Play your big draws like you would play a set every once and awhile.

i like betting draws on the flop/turn, but i dont like raising someone elses bet with a draw.

...

There are two types of draws and each one should be considered differntly.
One type is when your judgement is that you have 8/9 outs - for example you have 89d on a board of AdQd4s, this type of draws was nicely covered by all other posters here.

Another type of draws is when your judgement is that you have 14-15 outs
for example you have AdKd and the flop is 5d8d2c. You put your opponent on mid pair 99-JJ. In this case you can play it like you have the best hand. I may in some situations push this