How to Prevent Bathroom Mold
Use these few steps to prevent mold from appearing in your shower. Once it's there, it's a real hassle to remove.
When you're done, squeegee the walls off. This will eliminate most of the water (the problem)
Use the Fan
Make sure to keep the fan on during the shower, and half an hour afterward to make sure the moisture doesn't stay in your bathroom. Also make sure your fan is properly rated (CFMs) for your room using this formula: Length X Width X Height X 0.13 = CFM rating required. Also the lower the sone rating, the quieter the fan will be.
Seal Grout Lines
If you have tile, seal the grout lines annually to make sure they stay waterproof.