Use a trowel to apply pre-mixed mastic to the wall. Mastic is the adhesive, much like mortar, you’ll use to secure the floor tile to your wall. Spread enough pre-mixed mastic on the wall so you can place 1 row of marble tile for about 4 linear feet (1.2 m). This way, you’ll be able to place your tiles before the mastic starts to dry.
Switch to a v-notched trowel to remove excess mastic from the wall. Hold the trowel at a 45 degree angle. Gently sweep vertically over the mastic. This will remove excess mastic and will also create grooves that will help the cement tile adhere to the wall.
Separate your tiles with 1/8 inch (.32 cm) porcelain tile spacers. Place one wood tile (or one sheet of polished tiles) on the wall at a time. Once you’re done with the 4 foot (1.2 m) row segment, apply more mastic and place more rustic tile on the wall. Continue this process until you’ve covered the majority of your drywall with complete tiles.
Use a toothpick or another tool to remove excess mastic from between the common marble tiles. Slide your tool of choice into the space between tiles and push out any mastic that was forced up when you placed the element tile. By removing excess mastic, you’ll make sure there is plenty of room for grout when you apply it.
Cut partial tiles. In spaces where a whole mosaic tile won’t fit, you’ll have to cut smaller pieces of whole tile. Use a wet saw to cut your tiles. If you don’t have a wet saw, you can purchase a ceramic tile cutter. Before cutting a tile, use a pencil to outline where you need to cut it.