Then again if I hit top pair, make a bet, get called and then hit second pair on the turn I will often just check to show weakness against agressive players. Often they will respond with a big bet resulting in a bigger pot size. Against passive players I will have to gradually raise the pot myself to win as much as possible.

BTW: In the last 2 days I played 1000+ hands on the .5-1.0 NL tables, won 86% of my showdowns and made 540$ profits. So I doubt slow playing is killing me..