These tips can be used for the orignal xbox 360 and the slim model
1)Make sure your console is not placed on carpet as this can block up the air vents and make you console overheat.So what you can do is move the console to a place were it has more ventilation such as a table or a flat surface cupboard.This can help the xbox 360 dis pass heat more quickly and reduce the chances of overeheating in the future.
2)Get a small power hoover and suck up all the dirt and dust from the back air vents and side air vents.Dust can get between the cooling fans and this can slow down your fans which can also cause overheating.
3)After a long gaming session for example 4 hours or more it is best to turn off the console for at least 15 minutes.This is so the gpu and cpu can cool down to cool temperatures.Then turn back on the console again and repeat it every 4 hours just to keep you console happy.
4)Replace you stock xbox 360 fans with the talismoon whisper max.These fans are much quieter and faster than the stock fans but fitting them in your console will avoid you warranty.
5)Also make sure the power brick know as a power adapter or supply is well ventilated so the air around it can move freely.Many people keep there xbox consoles cool but forget or don't even think about keeping the power brick cool as well.Keeping the power brick cool is very important and is the most common cause of getting the three red rings of death.
6)Don't block the console air vents as this stops the hot air escaping out.
7)Try using the nyko intercooler it can help keep your console cooler because it help the hot air escape out from the console.Nyko intercoolers are really noisy, well you can give it a try some people say that they are a waste of money.