As with the kitchen, the bathroom is a "work room," and therefore one of the most important spaces in the home to get lighting right. They also tend to be smaller than all the other rooms in our home, and don't have as many (or as large) windows. Careful consideration of the General, Task and Accent lighting we add to this room will pay dividends in how the area functions and feels.
Note: As with any lighting project, but especially concerning the bathroom, it's important to consult a certified electrician before selecting any fittings. Different countries and areas have different safety laws regarding surrounding water and electricity, and it's important to ensure that the fixtures you're using are properly rated for use in a bathroom, and installed the appropriate distance from any water sources.
Ideally, all our bathrooms would be flooded with natural light, which helps us wake up in the morning and makes spaces feel larger and cleaner. And while natural lighting counts toward a space's general lighting, it's usually not enough in this room. We use the bathroom at all times of day and night (and darker times of year, of course), so good general lighting, through a series of potlights or a central pendant, is important here.
With task-oriented lighting in the bathroom, the most obvious place to start is the vanity, usually above the basin. For flossing, hair styling and makeup application, good lighting is required here. A light on each side of the mirror, at face level or just above, will provide the most flattering light. A single overhead light will sometimes lead to harsh shadows, but if it can't be avoided, try to keep the surrounding surfaces—the countertop, basin and walls— in light colors to bounce light back toward the centre of the mirror.
Task lighting is required elsewhere in the bathroom as well: over the shower/bathtub, and within any cupboards/closets that contain storage.
Accent lighting is probably less important in the bathroom than some other spaces, since we're (usually) not hanging out in this room for hours on end. But using light to highlight a feature of the space or create a cosy mood pays off in ambiance, so consider it if possible. Even occasional lights like candles work at times.
Accent lighting can also do double duty in a bathroom, if you're in the habit of leaving a light on overnight, for children or guests who might need to find their way in the middle of the night. Instead of a nightlight, some low-level LED lighting, or a wash of one wall, lights up the space just enough.