youre using a glass aquarium so you most likely have a screen lid right?

this is what i do with that kind of setup.

take off the screen lid and wrap it up with saran or cling wrap(you know those plastic kitchen wraps). wrap it up just over half way so you have space for the heat from the heat lamp to get through. if you are using a uth then you can wrap the whole thing but make sure the tank has enough ventilation.

oh and its not over yet

make sure you mist around every other day to help with humidity.

i also pour water in the substrate and mix it up when it gets dry. this works extemely well in maintaining proper humidity levels. but dont keep the substrate too wet, just a little damp. wet substrate can cause skin problems.

this works for me. im sure people here use different methods that work for them and hopefully they post them because i would like to know as well.

hope it works out for you.