Oil changes and lube regularly at proper intervals
Moved to synthetic where possible
Air filter replacement at intervals or when needed
Tire pressures
Wash and a wax
I used water wetter too and found no change in temps before or after.
Cooling has rarely been an issue. I added a 160 stat to the sedan (came with a 180 degree stat) when I towed with it and it remained no higher than 190, even when towing when it was hot out.
The suburban sits at 210 and doesn't move past it no matter what....so far.
The trans cooler in the sub seem ok. Never saw temps hit 200 degrees yet, even when towing at grade....came close, maybe 190, but not 200. I was thinking of adding a fan to the factory trans cooler. I like the trans to stay at about 155-175, which is where it sits mostly...until I tow at grade or when I tow and it's REAL hot out.