How can I properly install a tile over drywall?

To properly install tile over drywall, first ensure the drywall is clean and dry. Apply a waterproof membrane or primer to the drywall to prevent moisture damage. Then, use thin-set mortar to adhere the tiles to the drywall, ensuring they are evenly spaced and level. Grout the tiles once they are set, and seal the grout to protect it from stains and moisture.