Flush Draw Flop

[rsq]

I run into this often, and am not sure if I play this correctly.

Say you have a big hand, AA, KK, or flopped a set off a small pair.

Then the flop comes with 2 cards to a flush.

What approached have worked best to play the hand out? In the long run, is it always just better to slow play it and extract as much as possible, or better to protect the hand and see if others come along?

How do you play it at different situations during a tournament?

Thank you