Mark the measurements on a tile using a felt-tip pen (Image 1). If you have planned correctly, you will need approximate half-tiles, rather than slivers.
To score the tile, grip it in your tile cutter, with the glazed surface facing upward. Push the lever away from you to score along the marked guide line (Image 2).
Depending on the cutter design, either position the tile in the cutter's jaws or below its mechanism, before applying downward pressure to the lever to split the tile in two (Image 3).
Smooth any rough edges with a tile file (Image 4). Before placing cut tiles, spread adhesive on the back of the tile. It is easier to add adhesive to a cut tile than to the wall space.
Position the tile on the wall. To complete the wall, continue along the row to fill the horizontal gap (Image 5). Remove the vertical furring strip and repeat the process, working upward.