I periodically have had to bathe ferals and strays and since I treasure my arms and hate high doctor bills from cat bites and scratches, this is the system I have developed over time.
Cycle dry towels in the dryer prior to the bath. Take them out while they are toasty warm and put them somewhere that they can retain heat. I stick them in my microwave- but don't turn the oven on.
Take two buckets, fill one completely full of warm water, and the second bucket, fill it about 2/3 full of warm water. Take the cat and place her in the bucket that is 2/3's full rear feet first. She will then be standing, supported by the bucket and her claws are digging into the lip of the bucket, and not your arm. Scruff her gently by the neck, and using a cup, pour water from the full bucket all over her until she is nice and wet. Most cats are scared of the noise a sprayer or shower head makes. Using just a few drops of Dawn dishwashing lotion, scrub kitty, rinse her down, and tuck her into a warmed towel to get her dry.
This is quite literally the best way to bathe, because the cat feels safe, there is no slick surface to skid on, and because she wants to dig her claws into something, the lip of the bucket is a better alternative than your arm!