Installing Wall Tile
Once you've established the layout, you can start setting tile. Be sure your wall surface is thoroughly clean of dust and debris.
In most cases you should be able to use a pre-mixed adhesive for your wall tile. Make sure you check the label to see that it's right for your situation. Some pre-mixed adhesives won't work in high moisture areas.
Start setting your wall tile at your center section near the floor and work your way out and up.
Spreading out adhesives
Scoop some adhesive with your notched trowel and start spreading it evenly within one section using the straight edge of the trowel. Try not to cover up your layout lines -- you'll need them to align the tiles (although layout lines are easier to see through adhesive than through the mortar used for floor tiles).
Using the notched side of the trowel, comb out the adhesive. Hold it at a consistent angle (about 45 degrees) so the top of the adhesive has a uniform height. The pattern of the ridges isn't important.
Setting and spacing tile
Set the first tile in a corner, twisting it a little to set it into the adhesive. Press the tiles firmly into the adhesive. If the tiles don’t have spacers you may be able to twist them slightly as you place them to better set them into the adhesive. Do not slide the tiles into position. Test one of your early tiles by prying one up by its corner and looking on the back side. The adhesive should cover about 80% of the tile. If you see only parallel lines of adhesive, the ridges are too shallow. If the adhesive is squeezing out the sides, your ridges are too deep.
Set the remaining tiles, aligning them to your outside layout lines.
During installation, some sagging can occur so use a straight-edge to check this periodically. You may need to use small plastic wedges or tile spacers to keep the tiles at the proper height.
Cutting around obstacles
If you're tiling a shower or bathtub surround, you'll have to mark tiles for cuts to fit them around the plumbing. Set the neighboring tiles first, and use those to line up the tile you're marking.
You can make these cuts with a tile nippers, but don't try to go too fast. Nip off smaller chips to avoid taking off more than you need.
Don't try to be perfect with these cuts, most plumbing fixtures come with escutcheons that'll cover up the rough edges.
Cut straight lines with a tile cutter or tub saw.
Sometimes you won't be able to trowel the adhesive directly on the wall, like around obstacles or for small cut tiles in a corner. That's when you need to "back butter" the tiles individually.
Spread the adhesive on the back of the tile with a notched trowel. If the tile is too small you can also use a margin trowel to spread the adhesive.
Set the tile giving it a little twist to insure good contact with the underlayment.
Tub and shower accessories
As you are tiling showers and bathtub surrounds, leave opening for soap dishes and corner shelves.
After the tile adhesive is dry you can install these. Butter the backs with tile adhesive or use a silicone caulk.
Use masking tape to hold these pieces in place until the adhesive or silicone dries.