Measure for Tile
Before beginning to lay tile, start with a "dry layout" to get a good idea about accurate placement of the tiles (Image 1). This will help avoid having any partial tiles in the doorway.
Measure the span of the tiles in the doorway (Image 2), then transfer that measurement to mark the span at what will be the end of the row — the cement board where it fits flush against the tub. Then use a chalk line to snap a line, parallel to the wall, to serve as a guide for laying out the first section of tiles.
Lay out a row of evenly spaced tiles along the chalk line from the edge of the doorway to the tub. Unless you're lucky enough to get an exact fit, the last tile in each row (where the row meets the tub) will need to be cut to fit. An electric wet saw is used to cut each end tile for a precise fit (Image 3).
The electric wet saw can cut through hardened clay tiles quickly and easily, using a constant stream of water to prevent the blade from overheating.