Often when you tile a wall, you'll tile the whole wall, from top to bottom and end to end, so you don't have to worry about how to end the tile field on the wall because it just ends at an adjacent wall. For those projects where the tiled area stops in mid-wall, however, you'll need to trim out that edge since standard field tiles have unfinished edges that aren't meant to be exposed. One good solution is trim tiles, also called bullnose, which is finished on one edge.
Hang your field tiles, laying them out from the middle of the wall and setting then in tile adhesive, properly spaced. Leave the area open around the edges of the tile. Let the tiles set overnight.
Measure one of the edges of the tiled area where you want the trim tile to go. Find and mark the centre of the length.
Spread adhesive on the back of a trim tile with a tile trowel. Press the tile into place on the wall with one side of the tile next to your centre mark and the finished edge of the tile facing out from the tile field so the finished edge sits right next to bare wall.
Hang the rest of the trim tiles in the same manner, spreading adhesive on the backs and pressing them into place so they form the whole edge of the tiled area. Cut the pieces at the ends as needed to fit.
Let the tiles set for a day. Grout the whole tile surface (both field tiles and trim tiles) using your grout float to spread the grout and press it into the lines between the tiles. Use a slightly wet sponge to wipe off the residual grout from the surface.
Let the grout set for a day. Lay a thin, smooth bead of caulk along the edge of the trim tiles where they meet the wall, to seal it.
Wear eye protection when cutting tiles.