A bathroom renovation goes smoothly when the decisions are made before the work starts. Begin with the goal: is the room outdated, leaking, or just too small? That answer sets the scope.
Decide on the big pieces first: tub or walk-in shower, vanity size, and tile. Those drive the plumbing and the schedule. Tile and fixtures with long lead times should be ordered early.
Ask how the shower will be waterproofed. Tile alone does not stop water; the layers behind it do. In older homes, plan for surprises such as old plumbing or a soft subfloor once the walls are open.
Finally, get the scope, materials, and price in writing, and agree on how changes will be handled. A written estimate protects both sides.