Mourning geckos are healthiest in 60-70% ambient humidity with higher levels up to 80-90% daily. You can create and maintain these levels by misting 1-2x daily, depending on how well ventilated your enclosure is. However, make sure that the enclosure dries to 50-60% before misting again, as mold and fungus will start to grow otherwise.

Mist 1-2x/day with a spray bottle (I use the Exo Terra Mister), heavily enough to create droplets all over the terrarium. This provides an extra source of drinking water in addition to boosting humidity.

Photo contributed by Woodland Darts and Dragons @WMD_n_D

PRO TIP: Remove hard water spots with a cotton ball soaked in lemon juice (old spots may need help from a razor blade).