Like mentioned, cover 3/4 or more of the top with tinfoil, use a large water bowl and you can also place damp paper towels on top of hides and then just refresh the paper towels wetness as needed. Also if you are using a heat lamp, you are going to be fighting an uphill battle. You can also create humid hides with Tupperware storage containers with damp sphagnum moss in them and a U shaped door cut into the side that touches the lid of the container. You don't want to cut a complete circle door as a snake can get stuck.