Use only products approved by tile and grout manufacturers. Never use steam, pressurized water systems, abrasives, acids or harsh chemicals.
Always use PH neutral, no-rinse floor cleaning products. Use a damp mop (microfiber is best). Rinse the dirty mop in a separate bucket or laundry basin, so you keep the clean solution bucket free of dirt.
Always wipe down the shower after use. Drying the walls and floor will help prevent mold and mildew growth.
Eliminate bar soaps and use liquid shower soaps and gels. Soap scum build up on tile and grout is nothing more than bar soap that has re-hardened on the surface. Eliminating bar soaps will totally eliminate soap scum build up.
Clean the shower weekly with only products approved by all tile and grout manufacturers.
Always make sure there are no openings or cracks in the grout and caulked joints to prevent water damage and mold growth behind the tile.