When I started, the most obvious thing to me to use was a coating of some stuff called Plasti-Dip. I've used it for years to dip the handles of tools so they would offer a better grip. It supposedly comes in many colors, but around here I've mostly seen black, and once in awhile clear.
I've found that a single coat isn't adequate. My wife, who walks a few miles every day wore thru 1 coat in about 6 mo.s One of the older sticks I still use a lot is starting to wear thru.
I now put at least 3 coats on, sometimes 5.
I'm experimenting w. a more durable tip. I first coat the tip w. an epoxy resin that contains steel particles. It can be formed, and then sanded to shape w. some effort. Then I coat that w. the dip. One cane that I use frequently has that, and the signs of wear are minimal.
The primary advantage of the dip is that I can use it on any size or shape stick. Also, many of the places I walk are rather soggy. I can put the coating on as high as I like. 3" is average, but I've gone to 6" on a few pieces.