To cut tiles around an outlet, measure the faceplate and the tiles to know where you need to make the cuts, and mark the cut lines on the tiles. Use a tile cutter or a wet tile saw to cut the tiles along the marks. After you cut the tile, make additional small cuts, for example, to fit the screws in the faceplate of an outlet. Use tile snips to trim the tiles.
Usually, it is necessary to cut four or two tiles to fit an outlet in them. This depends on the outlet size and placement. To measure the side and position of the cuts, attach the outlet faceplate to the tiles. The faceplate of an outlet has to overlap the tiles, so add about 1/4 inch to the measurement, so that the tile edge is going to be underneath the faceplate. Remember to measure and check the marks for cuts several times, as you can't go back after you cut the tiles.
If you have no previous experience in cutting tiles, read more on how to do it, and practice on the tiles you don't need. Always place the tiles you are cutting onto a hard surface, so that they don't crack, and don't push the saw onto the tile too hard.