|Use a can or compressed air and blow out all vents and openable ports.|
A 'chill pad' or 'cooling pad' is helpful, just make sure that no vents are blocked in any way.
Take actual temperature readings with HWMonitor. post temp at idle, after working or internet, and after video or gaming. If temps are actually high after blowing dust out better, you may need to open it to clean it better or have it cleaned out by a pro. Under rare or extreme conditions, you might need more done to fix this issue.
You have to be a little bit crazy to keep you from going insane.