Measure the distance between the last full tile you installed and the wall or edge of your installation area. Mark that distance on the back of your tile with a pencil or marker.
Cut along the marked line with tin snips to sever the tile to the proper size for your edge area. Line up the tile with the appropriate space to make sure it fits.
Spread a ¼-inch bead of adhesive caulk ½ inch from the perimeter of the cut tile on all sides, as well as straight up the middle of the cut tile. Use a putty knife to smooth the adhesive so that it is flat against the tile and does not cause the tile to push out from the wall.
Firmly press the tile into place and hold it there for one to two minutes, until the adhesive bonds with the ceiling enough to hold the border tile in place.
Shoot three galvanized staples through the tile along every edge except the one that touches the wall. The staples should sit ¼ inch from the edges.
Repeat measuring, gluing and stapling each tin border tile. Measure each individually; do not assume that the distance is the same between tile and wall for each tile that needs to be cut.