Start with the face
A ceiling full of light does not guarantee a useful mirror. An overhead source can leave facial features in shadow even while the floor is bright. I start by testing how the face is lit at the actual mirror position.
Light from beside or around the mirror can help, but position, diffusion and reflections still need attention.
Separate precision from atmosphere
Shaving, makeup and cleaning need different things from a quiet bath or a late-night visit. Layers let the room respond without making the mirror lighting do every job.
A discreet low-level source can make a night setting comfortable. It should still reveal the route and any changes of level.
Keep the fitting suitable for the location
Bathroom electrical requirements depend on the exact installation. Have the electrician assess locations and suitable equipment. A decorative fitting is not appropriate simply because it looks good in a bathroom photograph.
Test the finishes and light together. Warmth, brightness and colour quality all contribute. A restrained scheme can feel calm while remaining properly useful.