Ambient light
The general light that fills a room, from recessed lights, a central fixture, or both. It should be even and comfortable, never harsh.
Task light
Focused light where you work: pendants over an island, under-cabinet lights along the counter, sconces at a vanity, and a lamp by the reading chair.
Accent light
Light that draws the eye to something: art, shelving, a fireplace, the texture of a wall, or a tree outside the window.
Color and quality
Color temperature is measured in kelvin. Around 2700K reads warm and residential, like incandescent light. Look for a color rendering index of 90 or higher, so skin tones, wood, and fabrics look true.
Controls
Put each layer on its own dimmer, and a single room can go from bright and practical to soft and quiet. Smart dimmers like Lutron Caseta can set a whole room with one touch.