Here is a play that I've become very fond of and seems to be working well. It works best if you're heads-up and in position on a relatively tight player who doesn't generally bet on the come.
Here's an example:
UTG raises, I call on button with 56s, no other callersw. Flop comes 47Q with none of my suit but two to another suit. UTG bets pot, meaning he probably has a hand, QK or better, and I call, looking to either complete my deceptive straight draw and take down a big pot or bluff the completed flush draw. If a blank falls on the turn, I will call another decent sized bet (probably up to 2/3 or 3/4 pot-size or so, assuming I'll have enough left in my stack to make a bluff with some muscle or get paid off big on the river) looking for my straight or the flush possibility to come on the river.
If the flush draw completes on the turn and it's checked to me, I'll probably check behind or make a small bet--representing a strong flush--and then bet huge on the river. Similarly, if the flush comes on the river, I'm betting huge when the other guy checks it to me and 9 times out of 10 I'll steal the pot. If the third flush card comes on the turn and I'm bet into, then it really depends on my read. If I think he has either a set or top pair or better and the nut draw and won't be able to get away from it, I'll fold. If I think he's bluffing or has a hand he'll fold to a big bet, I'll raise big. And obviously, if I get one of my six outs for my untainted straight, I'm in a prime position to win a big pot (the other guy is likely to bet on turn and river with a strong hand and no flush, and a big raise could easily be misread as a missed flush), so I'll bet or raise as much as I think the other guy will call. If the flush draw AND my straight draw complete, I'd probably make a relatively small value bet, since I probably won't be able to sell my hand for very much with the flush draw out.
So, the next time you have an OESD heads up, consider that you might have 15 outs instead of just 8.