What temps are you expecting? A watercooler can never cool below ambient. What you should base your watercooler temps on are full load temps (let it run a couple hours to thoroughly saturate the radiator and water with heat). I am currently posting on a 1.6A @ 2.1ghz (can do 2.4, but my power supply is bottoming out there). My posting temps are 28C, which I consider pretty dang good since its only 7C over my ambient temp in my room. It hits full load temps at 33C (@ this speed). At 2400 it hits 38C under full load, which is decent.
As far as tips go, just make sure you feed your radiator outside air (never pump air from inside case out). Make sure it isn't restricted on its intake either. If its trying to draw through small air gaps, it won't cool as well. But I can't see anything wrong with your temps as they are now, unless your ambient (room temp) is 15C or less.