Betting out my flush draw

I want to know how you money makers handle a strong flush draw after the flop. This is how I handle it. Tell me if I'm correct in my method.

If checked to me, I bet out half the pot if it's not giant. If it's a huge pot I bet out a quarter or whatever isn't overextending myself but still taking a stab at it while drawing.

If one big blind bet to me I raise to two big blind if I have an over card. When the bet is more, this is when it gets confusing to me. I know I have 9 outs, so I have a 35% shot to improve with two cards to go, or 20% if I plan to see one card.

I just don't know if I should stay in here if the odds are right given that there are people betting behind me. Do you bail here if there's a chance someone will raise and blow your pot odds?

If someone could explain how they handle this unique situation perfectly, then please let me know. I feel like it's a definate hole in my limit and no limit game.