I put a cup of water with the newspaper soaking in and above the water. It helps out a little if you don't have a mister, humidifier or other water devices. I have Cypress Mulch as my substrated and it seems to hold water pretty well.

I still need to work out some more kinks as my humidity is still falling below 70%. I think since I have a slight opening for the heat emitter the humidity gets sucked out of there.

The breeder I got mine from told me to soak the mulch with good amount of water. Once I do that he also then said to mist as well.