Quality sleeping bag and mat. If you are backpacking, it’s harder, car camping you can get a good air mattress and a
Ziggy’s sleeping back, I have the Antarctic Hunter (-60F) and love it, it’s plenty cool in Moab heat adjusting with the zipper but very warm zipped up in the cold.
Those two items made me go from “I hate this, I never sleep.” To finally getting a few hours of deep, dreaming sleep a night
(I’m a notorious bad camping sleeper, so the improvement was worth the $300 for the sleeping bag.