Humidity is less important with getting a snake to shed properly than hydration. Make sure you do your daily water changes (in the evening if you can). The snake will drink the water when it's fresh, snakes are kind of like us in that they don't care for stale water unless they are dying. Just because you don't see them drinking doesn't mean it's not. Check your temps as well. In some locales the 90 recommended hotspot can be dropped down a few degrees as long as it doesn't affect your ambients too much and this will allow the snake to metabolize water more slowly meaning it's more hydrated.
Secondly, in regards to stuck sheds. Its happened to the best/pretty much most of us when we were starting out. I've found the best method is to take a hand towel and get it wet with warm water. Wring it out a bit, then put the towel and your snake into either a pillow case or perhaps an extra small tub/critter keeper. This forces the snake to crawl through the wet towel which is rough and grips the dry shed skin very well. Leave it in the pillow case or tub for about 20 minutes or so, you can repeat this once a day for a few days.
Pulling shed skin off of a snake is incredibly stressful and can actually cause scale damage if you don't do it right or if it isn't loosened enough.
Anyways, congratulations on your new snake and good luck!