How to Install Adhesive Backed Vinyl Tile on Walls

Instead of wall paper, paneling, or paint, have you considered another option?  Vinyl floor tiles are an attractive alternative to the other three methods of dressing up a room.  As long as the walls stay dry (I would avoid putting in bathroom or kitchen walls) there is no problem with mounting some vinyl wall tiles to your flat surfaces.  A few preparatory steps should be conducted first, however, to ensure that the adhesive does not become compromised as the days and years go on.

Preparation

1. Scrape any paint or wallpaper from the walls before attaching vinyl tiles.  If there is any loose backing the adhesive on the vinyl will not be sticking to the wall properly and the integrity of the adhesive will be lost.  This will result in the tiles coming loose from the wall and bubbling in places.
2. Give the walls a sponge bath.  Any dust that is on the walls will get onto the adhesive and keep it from sticking to the surface of the wall.  Dust is an enemy of anything sticky, from tape to glue, so make sure that the walls are free of dust and grime.  If there is any oil, use a degreaser to remove it.  Adhesive will not stick to oily surfaces either.
3. Sand the surface.  If you make the surface that you are going to stick the adhesive tiles to a little bit rough then you will have a better seal because the adhesive will have more surface area to cling to.  It is much the same as when one rough-sands their walls before putting stucco on it to help keep the concrete on the wall. 
4. Vacuum the wall.  If you have rough-sanded the wall there is now dust in those crevasses.  If you have a wand style vaccuum or a Shop-Vac then do a once-over with the vacuum to remove any dust that may be trapped in the sanded surface.

Install Tile

1. Use a level and draw a horizontal and vertical level line on the wall.  The center, where the two lines intersect, will be the starting point for installing the tile.  Begin installing the tile in the middle of the wall to assure continuity of appearance.
2. To install square tiles in a diamond pattern, once the perpendicular lines have been drawn, draw angle lines diagonally across the intersection.  You will know it is even by measuring from the horzontal and vertical lines to the diagonal line.  If the measurement is the same then the diagonal is correct.
3. Remove the backing from the first tile.  Carefully (do not touch the adhesive with fingers) put one corner of the tile in the corner of the marks on the wall.  Press firmly to that one corner making sure that it is lining up with the marks.  Once it is where you want it then press the rest of the tile firmly onto the wall.  A rolling pin or a large dowel will help you to press into the sanded area and make a better connection.
4. Continue around the first tile with the rest of the tiles until you reach the corners.  It is crucial that corner tiles are cut properly or they will buckle or leave gaps on the edge.  Measure twice and cut once.  If you are using a definite pattern on your tiles make sure you are cutting off the correct side of the tile to maintain the pattern.
5. Cutting the tile can be done with an Exacto-Knife or a utility knife.  Carefully cut the tiles on a cutting board or other piece of wood, using a straight-edge like a ruler to ensure a straight cut.  Score the face side surface of the tile and then fold at the score to snap the excess off.  The cut surface should be in the corner.
6. if your corner surfaces are not perfect it is easy to mask by purchasing some corner trim and covering up the flaws.  It will make the wall look more finished and give it a little additional style.

Additonal comments

Because vinyl adhesive tiles come in so many styles and colors, they are a great idea for areas where children are likely to play.  Kids rooms are ideal locations for vinyl tile.  It is very easy to wash and also durable.  Bouncing balls and an occasional flying truck will not make as big a mess of a vinyl tile wall.  If one gets ripped just have more tiles on hand, remove the damaged tile with a utility knife and replace with a new one and problem solved.

I have heard it is not recommended to use self-adhesive vinyl tiles in a damp area like bathroom walls but I cannot say whether it is a good idea or not.  Personally I've been wanting to try anyway, just to see what would happen.  I know I used tile glue and self-adhesive vinyl tiles on the bathroom floor and it was nearly impossible to rip up to put down ceramic tile!