My understanding is- disc rot is, most commonly, a result of defects from the disc's manufacturing- a bit of air or dirt that got caught inside the layers of the disc & breaks down the data layer from the inside. This is why it tends to be more common on earlier discs, from before standards for manufacturing were refined- but it can happen to any disc.
Becuase the offending bit of crud is, literally, a part of the disc itself, you can't really stop disc rot. All the above advice- use a proper case, cool dry environment, etc. are good to be doing regardless- these prevent the disc from being damaged due to preventable measures. Otherwise? If it's gonna go, it'll go- there's nothing you can really do about it.
By my experience, even if you've got early signs of possible rot, there's a good likelihood your game will continue to work for years to come- I've got more than one disc with clouding or even pinholes, and so far nothing's actually failed. You might seek out a better condition replacement if it's a favorite- but beside that, you shouldn't sweat it too much. Just take care of your stuff in general. Scratches or heat damage will kill your game way faster than rot ever will!