I rarely have any shed problems, but it does happen on occasion. If I see that one of my snakes is having difficulty, I will place the snake in a container with a tight-fitting lid, along with some paper towels that I've cut into strips, and dampened with warm water. I put the snake inside, then put the container back into the cage, on the warm side. About an hour later, the skin has come off perfectly. Got this handy-dandy tip from Don Soderberg at South Mountain Reptiles.
This method has worked for me for years, but you may want to try different methods, and see what works best for you. I like this because the snake is only exposed to the moisture for an hour, so I don't worry about any adverse effects.
Kathy