Measure the distance from the surrounding tiles to the edge of the socket opening.
Transfer the measurements to the edges of the cut-out tile with a permanent marker. Make allowance for the grout line so the finished tile aligns properly with the surrounding tiles. Grout lines for wall tiles are usually between ¼ and 3/8 inch.
Use a straightedge to connect the two edge marks with the permanent marker. When you’re done, hold the tile in position next to the socket to check the accuracy of your marks.
Cut along the marked lines with a tile saw. Discard the waste piece and place the tile in position.
Measure the distance between the surrounding tiles and the edges of the socket opening. For a cutout, make two measurements for each corner. Measure the distance from the top or bottom, as well as the distance from the outside to the opening.
Mark each corner of the cutout with a permanent marker.
Use a straightedge to join the four corners with permanent marker.
Use a drill and a diamond bit to drill a hole just inside the marks on each of the four corners.
Thread the diamond blade through one of the holes in the tile, and attach the blade in the coping saw frame.
Cut along each of the marked lines with the coping saw and remove the cutout. Place the tile on the edge of a stable surface while cutting. Providing adequate support for the tile reduces the risk of breaking it.