Trimming down your bathroom's water waste without breaking the bank

I've been trying to cut down on my water bill lately, and figured the bathroom was a good place to start. First thing I did was swap out my showerhead for one of those low-flow ones—honestly, didn't even notice much difference in water pressure. Then I installed a dual-flush toilet kit myself (surprisingly easy, you know, even for someone who's not exactly handy). Um, next up I'm thinking about faucet aerators. Anyone got other ideas or maybe better tricks to save water in the bathroom?