On the flop with four people remaining you started the betting @ 18% of the pot. With the club flush draw @ 36%, you should have bet AT LEAST THAT AMOUNT (ex) $0.50 or .60. penny tables entice callers that shouldn't be calling, so you probably could have had a couple callers with that bet.

In summary: When you have the best hand, represent and bet large. Anything else is an opportunity to catch up. If you have pocket aces after the flop, your opponent(s) have a better opportunity of improving their hand than you do).