brummie tiler

hi guys, just priced up a job today its a hallway, small floor about 3m2 and wall tiling half way up the stairs about 8m2. This guy has had to redecorate 5 times in the last 6 years so he has decided to have it tiled as they should withstand the flooding much better. Just looking for some advice to make sure Iam gfoing about this in the right way. The floor is concrete and walls newly plastered, was going to tank the area and use a flexi addy on both walls and floor, anything else i should be thinking of?