In my experience, best practices involve selecting the right candle/wax, as others have stated. Some sort of protective o? for easier removal is nice, unless the Dom(me) is a bit more sadistic.

I prefer to warm the area up with some mild impact play, although once you have a feel for a submissive’s tolerance, sometimes you can forego. Height from which you’re dripping is critical. Too far away and the wax has sufficiently cooled to not stick. Too close and you risk a burn. Comes down to knowing your bottom and their likes/dislikes.

Just my 2?
-Sarin