I learnt how to tile a shower by doing it!! A couple of reno shows, a tiling book and a few web sites gave me the basics and off I went. Tiling is so easy anyone can do it, but practice helps.
Go to a large hardware chain store and attend a quick tiling presentation. Tile the wall on your shed or the bench in your laundry and get the hang of it.
There are some preliminary duties to attend to before you start, including wet sealing: go to my Wet Sealing a Bathroom page here. Do a rough guess at the number of tiles you want and add 10 percent fro wastage. Assemble tools such as tile cutters, tile drills and glue spreaders.
Start with a timber seat around the wall to sit the first row of bathroom wall tiles on. Make the top edge exactly level and about three quarters of a tile from the lip of the shower base.
Some tilers recommend screeding a layer of tile glue over a section with a glue speader and then tiling that section. Others I have watched apply tile glue to each tile with a spatula separately. The second method is for pros as it is difficult to get them exactly flat time after time.
Mark a vertical line about one tile width from the corner and use it as a guide as you go vertically. Take care to use the spacers to keep each bathroom wall tile square and go back frequently to check the tiles haven't sagged off square.
Use good quality tile glue and small spacers, and keep checking your lines as you go. If you haven't grouted before, try it on a non visible side first. A creamy mixture is the key so read the directions carefully. I have a 'How to Grout' page here. Go to my floor tiling page for more info and graphics. Put a bead of silicon down the corners and along the bottom edge of the base tile to limit water movement. Now its time to connect the taps and install the glass.