Could i extract more Value?

I think you should be raising pre flop after he limps. This hand is not an outstanding one to play post flop with and taking the initiative helps compensate for the fact that you are out of position. His min raise on the turn is quite weak, but I imagine he is trying to represent the flush. By the river the only hands that are beating you are 88 and 66. Since he is repping the flush I would bet bigger on the river. Especially since he is calling you with K high...In general I think a rule that I try to follow in the micros is that you should try to make your value bets BIGGER. if you are thinking 1/3 might be enough, often you can actually size it up and still get called because people do not fold.

After the turn action, I would pot or over pot the river because he would have a hard time folding over pairs, 6x, flush, and I think this is the run out that gets you paid as bigger boat seemingly completes on board raising a greater doubt in the villain's mind.