Another thought: make sure that any plastic air dam that came on teh car underneath teh front end is still there; these are critical on some body designs to direct airflow through (not around) the radiator to cool it.
If you have A/C, make sure that the condenser fins are not blocked with dirt or debris blocking airflow. Believe it or not, I have had some cars in our shop that I managed to lower the AC temepratures by 10 degrees just by using a pressure washer to wash bugs and dirt out of the core fins. remember, all the air going through the radiator has to pass through the condenser first.
Also, is it actually overheating? If it is just the gauge reading indicating overheating, verify that you dont have a faulty gauge by measuring the engine temp directly.
If this vehicle has a serpentine belt, make sure it is routed correctly. I have seen incorrrectly routed belts which were spinning a water pump backwards cause overheating problems.
Does engine power seem normal? A restricted exhaust, failed CAT, very late ignition timing, and other problems can cause an engine to produce way more waste heat than normal; usually there will be power loss or other symptoms as well.
the fan isnt spinning backwards for some reason, is it? It should blow air towards the engine when the vehicle is standing still.