Keep it in a well ventilated space
Open the top part of the case so it's easier for the heat to get out.

Buy a cooler for it!

Do anything less of what I'm about to tell you is iffy, may help or may not...

Best way to go about it is to identify what is overheating on you, check the secondary error code next time you get the RROD.

It'll be 0011,0012 or 0013 if it's a true overheat issue..

You can replace the thermal with some fresh thermal, re adjust the bolts or ad the x clamp fix kit to it and go ahead and 12v mod your fan..

The recommended way is to send it off for a repair for a Reflow and x clamp mod,12v,thermal...Best part, it'll come with a warranty from the repair place..

If you need the service, check me out below, little house..Click..

-360RepairKings