Mark the locations of the necessary cuts on the tile, using a wax pencil. Double-check the cut locations and trial-fit the tile before making any cuts.
Score the glazed or glass surface of the tile with a glass cutter along the cut marks. Press hard enough so the cutter penetrates the glaze or glass surface. The tile remains in one piece held together by the backing material.
Nip away the waste material from the tile. A tile nipper resembles a pair of pliers with jaws that are at right angles to the handles. Compress the jaws to nip or break off a small portion of the tile. Continue to snap off small pieces of tile until you reach the score lines made by the glass cutter.
Rub the cut edges of the tile with 60-grit sandpaper. This smooths any sharp edges and can prevent cuts or scratches while handling the tile.