I used to suffer from serious jock itch but read about the following procedure which has really helped: Upon exiting the shower use the dry ends of the towel to dry the crotch area. Then dry the rest of the body. Then use a small dry washrag to AGAIN dry the crotch area.
One step I added is to use a good anti-fungal liquid body wash on the crotch area only (I use a bar of soap for the rest of the body). I like a product called Black Bottle. I believe it's one of the only products that actually contains the very effective ingredient ingredient Tolnaftate. The others usually just contain tea tree oil which I've found to be less effective. I've found this regimen to be VERY effective.