Do you have confidence in the accuracy of your temperature gauge?  Do you
have any means to verify its indication?  How much overheat are you seeing?
Red zone?

When the car is sitting there running with the hood up how does the air flow
from the fans seem to you?  Powerful?

If not then my suspicions would be that the fan motors might not be getting
enough voltage (relay or connection problem) or their ground connection is
not up to snuff.

If there is weak air flow and there is not an electrical problem can you
tell if the air flow shrouds are intact and directing all the air the fans
are pulling through the radiator and not bypassing it?

Is there nothing plugging up the external radiator fins or the air
conditioner's evaporator in front of the radiator?

Good tension on the drive belt to the water pump?  Does the pump spin
smoothly when the belt is off?

Rechecked coolant level after the initial refill?

If the usual suspects are not to blame then the uglier possibilities start
to come to mind, like head gasket woes.  Let's hope that this not the case.