Remove existing tile, wallpaper or other wall coverings to prepare the surface. Remove any remaining glue or adhesive from the old covering. Wipe down the wall to remove any leftover dust or debris.
Repair any blemishes on the existing drywall by applying spackling compound with a putty knife. Allow the spackle to dry before sanding it lightly to smooth. Wipe away any dust.
Measure the wall area that you plan to tile so you are able to lay out your pattern. Mark the middle of each wall to help balance the tiling pattern.
Lay out your tile pattern if you are using different colors or designs of tiles. Determine how you will tile before placing the borders around the main tile.
Use the level to mark a level line horizontally on the wall. Use this line to ensure all the rows are level when setting your first row.
Spread a thin layer of tile adhesive -- with a notched trowel -- along the bottom of the wall you want to tile. Install the bottom row of tiles using the marked line and the level to ensure you get a straight row. Press each tile firmly into the adhesive.
Place additional tiles, spreading the adhesive in small areas of about 2 feet at a time. Put tile spacers between the tiles to maintain even grout lines. Hold the level up to the tile occasionally to ensure you continue with level rows.
Cut edge pieces to fit if your area doesn't end with whole tiles. Cut out holes for electrical outlets or other cutouts using the tile saw. Install these pieces.
Add the border tile along the edge of the area. Let the adhesive set at least 24 hours before grouting the wall.
Scoop up the grout with a grout float. Spread the grout over the tile joints, holding the float at 45 degrees as you smooth and press the grout into the spaces. Go back over the tiles with the float to remove the excess grout, being careful not to dig any out of the cracks.
Clean off the tiles after 20 minutes by gently wiping them with a clean, wet sponge. Apply the silicone caulk along the bottom, especially if you're tiling above a sink or in the kitchen.