Top tips for a quieter console:
- Remove any discs that are in there if you aren't using it. My X sounds like a fucking washing machine if I leave a disc in.
- Vac out the vents, front and back, at least once a month to prevent dust smothering the components. Placing your hand over the front vents while vaccing out the back and visa versa, helps a lot.
- Don't put them in enclosed spaces as the fans will run faster to keep the console cooled.
Solid tips, but especially if you have an launch PS4 or Pro, one more. Both can (not necessarily will, it's dumb luck basically) have a manufacturing (or assembly) flaw that really shouldn't exist - that the thermal paste is poorly applied (and it's not very high quality to begin with). Changing the thermal paste will void your warranty so the usual warnings apply, but really, if you've ever put a PC together you should have the required skills. There are several guides/YouTube videos available online for instructions.
....but as said, the usual warnings apply, I'm not responsible for people tinkering with their consoles.
Edit: oh one more, if you have a Slim or a Pro, the top comes off without any tools so you can easily clean some of the innards. This will
not void your warranty - it does take a bit of force and I was quite certain I'm going to break the top cover first time I removed it, but it's really quite sturdy plastic (which also makes it a bit trickier to remove). Again, instructions can be found online.