A lot of cooling has to do with the way the air flows in the box. It's not really helpful to have 4 fans if they're blowing air out at the bottom and sucking air in at the top, hot air rises after all. Cables and cards can cause obstructions in air flow too. You should have fans blowing out air at the top and sucking air in at the bottom-front, that way the warm air gets expelled and cooler air is brought in. This creates an 'S' pattern of airflow in the case. Make sure cables are bundled up and out of the way, that's very important.
Dust also keeps heat in the CPU, make sure you clean the dust out of the case every few months or so. In some cases, these simply things can increase cooling inside the case by a lot, lowering the CPU temp by 10 degrees C or more (at least that's what it did with my friend's computer, which was a mess of cables and dust before I helped him do these few simple things).