The first step is to turn off the electricity to the outlets and switches in the area of the backsplash. This is a safety measure as well as part of the construction process. Locate the fuse or breaker box, and switch the breakers off or remove the fuses. You should test the outlets by plugging an electrical tool into the outlet. Check the switches by seeing whether the lights come on when the switches are thrown. Remove the outlet and switch covers.
The addition of a backsplash increases the thickness of the wall. If the electrical boxes fit flush with the old wall, they need to be extended to fit flush with the front of the backsplash. Extend the electrical boxes by the thickness of the backsplash material. This involves removing the electrical outlet or switch mechanism from the box and fitting an extender on the frame of the box before replacing the outlet or switch mechanism. If you are not comfortable working with electrical fixtures, you might want to contract a licensed electrician for this task.
The process of cutting the tile to fit around the outlets and switches varies with the type of tile. Glass tiles might be cut with a glass cutter, while ceramic tiles are often cut using a water-cooled tile saw. Measure and mark the tile before making the cuts. The cuts need to be accurate enough so that any gaps between the tile and outlet box are covered by the outlet or switch cover.
Finish the backsplash, including grouting, before covering the outlets. To cover any inaccurate cuts, use oversized covers. Turn on the electricity, and check the outlets and switches for proper operations.