Disagree with this- you can't successfully fit skirting and architrave over tiling. Where you are going for full height, floor to ceiling tiling you generally don't fit a skirting, use a half floor tile to form the skirting around the wall. However it is still normal practice to fit an architrave in such a scenario and this is fitted before tiling and tiles are carried up to the edge of same. In more modern, contemporary build skirtings and architraves are often dispensed with and special plastic trims are used to form shadow lines in the plasterwork. The tiler will use these trims as his starting point. Hard to explain in text only....