Start by setting the tile to be cut on top of the full-size tile closest to the corner. Be sure its edges are perfectly aligned with the tile below. Next, set another full tile on top with one edge pressed against the corner. Run a felt-tip pen or pencil along the edge of the top tile to mark the first cut line onto the middle tile. Now move the top two tiles to the other side of the corner and repeat the process to mark the second cut line. The area outlined by the two intersecting cut lines is the part of the tile that must be notched out.
Direct-marking eliminates measuring mistakes and works great for all types of floor tile, including glazed ceramic, vinyl, wood parquet and plastic laminate.