Establish a horizontal level line all the way around the room which corresponds to a grout joint.
Before any tiles are set, it's crucial to determine the correct tile layout. A good starting point is to establish a horizontal line all the way around the bathroom at a height which will correspond to a grout joint. Most professional tilers will put this line a little under half height of the wall, above bath height, sink and toilet (so as to avoid having the sanitary ware breaking up this horizontal line, which is a key reference point as tiling is in progress).
Determining the best height requires some judgement as every room is different. But here's some pointers as to how you might go about it:
Measure half vertical height on a stretch of wall uninterupted by sanitaryware and try that as a grout line, measuring tiles to the floor or ceiling. If that height leaves less than half a tile at the top and bottom, move the line by half a tile up or down. Now test out this height around the bath and window. Does it leave any small strips around the bath or just below the window or just above? If so, adjust accordingly to erradicate the strips ie if you've an one inch strip above the bath, move the line down an inch. If you've a one inch strip below the window sill, move everything up an inch.
Once you are happy you've found the right height, draw this line all the way around the room. Now double check that you won't be left with narrow strips at the floor, or ceiling, or bath or window edges. Sometimes it's impossible to avoid a strip somewhere and it just comes down to judgement as to what will work best. Generally though, a strip at the floor will be less noticeable than one at the ceiling or window.
Establish a vertical guide line on each wall corresponding to a grout joint.
Again find the mid-point along the horizontal distance of the wall and determine how many tiles will fit either side and whether a strip will be left at the wall. If there's less than half a tile at the wall edge, move the vertical line (either direction, it doesn't matter) by half a tile. Rarely should you start tiling from one wall, unless you're very confident that the wall is vertical from top to bottom, and that you'll be left with a good size cut at the other side. By instead finding the mid point, you'll achieve a more balanced look with equal cuts on each side.
Tile the bottom half of the bathroom below the horizontal level line all the way round.
Choose an appropriate trowel for the size of tile being used. If you're unsure see these tiling tools.
Rubi Tile Cutters, Scaffolding Tools, Tape Measures & Measuring Tools UK Spread the selected adhesive over an area which can be comfortably tiled within about 10 minutes (the adhesive will start to skin over once spread so you can't afford to leave it to long before placing the tile).
Place the first tile just below the horizontal reference line you've established, and to the side of the vertical line you've drawn. Work down and to the side untill you've filled that section of the wall. Modern adesives have fairly high grab so you should find that although the tiles slip down a litte initially, they should firm up within minutes and then stop moving allowing you to work down to the floor and put in the lowest tile.
There are factors which affect the grab of the adhesive. Primarily being 1) How absorbent the background surface is (less absorbent surfaces such as tile on tile, or gloss paint will slip more than an more absobent surface like plaster, or plaster board, or tile backing board. 2) How much adhesive is used. If excessive adhesive is used (say to make up for an imperfection in the wall) then more slip will occur. Caution is required if you need to build out a wall excessively since adhesives have a recommend maximum depth which should not be exceeded.
If you find you get excessive slippage on the tiles then you may need to fix a batten to support the tiles as you go.
Use tile spacing pegs to maintain even spacing between the tiles and keep the grout joints fairly clean of adhesive. It's much easier to clean them with cardboard and a sponge whilst the adhesive is wet than once it has dried.
Use your spirit level to check that you achieve a good horizontal line to the top of this section and a good vertical line to the side. If that's done and the spacing between tiles is maintained properly, then that should be fine.
Tile the top half of the bathroom.
Once the bottom half of the bathroom has been tiled, then generally the top half is fairly straightforward. You've now got the bottom half tiles giving you the horizontal line all the way round. Just tile small areas at a time, working outwards from a vertical line running up the full height of the wall, and upwards from the below tiles. Use spacing pegs to maintain even spacing and check horizontal and verticals regularly with a spirit level.
Discussions on all aspects of tiling & installing tiles in the tiling forum.
Acceleracers Track Mod Champion!
Tiling Bathroom Walls 
Linear Mode
