If i notice my snakes are about to go into shed i give them a little plastic hide box thing with a hole cut into the lid, filled with moist coconut substrate stuff. They usually hang out in there quite a bit before shedding. Or you can just make sure their water bowl is be enough to allow the snake to soak if it chooses. But yeah, you pretty much don't have to do anything.
but like spaniard said
They get blue-ish, then clear up and look normal for a day or two, and then shed. So if 3 or 4 days go by, and you look at your snake and it looks normal but you can't find the shed, it didn't eat it or anything, just be patient. That confused me when i first started out with snakes too!
oh yeah, i like to feed within a day or two after shedding. They usually miss a meal while in blue, so they're pretty empty, and i figure shedding is a pretty labor-intesive business and they deserve some food!