to increase humidity:
1. i forget what it is called but there is this seal and stick saran wrap stuff--get some of that and cover about 2-3 of the screen tops with it making sure to cover the hot side to hold in the most humidity.
2. make a humid hide. cut a hole into the top or a tupperware container that is similar in size to the hides that you currently use. put damp paper towels or sphagnum moss in the container and mist every few days to keep damp.
3. use a larger water dish and place it over your heat source. a dish made out of ceramic will conduct the heat and cause more of the water to evaporate into the air and raise the humidity.