Installing a towel bar or toilet-paper holder often requires drilling through glazed ceramic tile, which is no easy task. Use a carbide-tipped masonry bit; regular twist-drill bits can't cut through the fire-hardened glaze. You'll also need to keep the bit from slipping off the glossy surface.
The secret: Put two strips of masking tape onto the tile in an X pattern as shown above. Then drill through the tape — you'll feel the bit grind as it goes through the glazing. Drill through the tile and into the drywall or backer board. Just be sure to lighten pressure at the end to ensure a clean hole at the rear of the drywall or backer board to accommodate a hollow-wall fastener.
