Wear gloves, goggles, and an N95 or better mask
Ventilate the area by opening windows and using fans
Fix the moisture source first
Remove and discard porous materials with heavy mold growth
Clean hard surfaces with soap and water
Use a mold-killing cleaner or diluted bleach on nonporous surfaces
Scrub the area thoroughly
Dry the area completely
Run a dehumidifier to keep humidity low
Clean or replace HVAC filters
Wash contaminated fabrics in hot water
Seal and dispose of moldy debris in bags
Keep the area dry and monitor for regrowth
Call a professional for large infestations or hidden mold