Reduce moisture & remove standing water
IDEAL moisture levels of 30%-50% not exceeding 60%
Things you can do to reduce mold growth:
Use a Dehumidifier (applicable to surface area)
Use the exhaust to vent warm air whenever there is moisture generating from appliances such as the oven, or shower vapor etc...
Repair leaks ASAP and clean up any excess liquid and/or vent out any moisture.
Make sure the HVAC systems are routinely cleaned. It will trap & clog overtime from dust particles and dirt accumulated in the air.