Ceiling painting is a different job from the walls. It needs different equipment and a painter who has done it before.
Paint the ceiling before the walls. The order is top first, then walls, then doors and windows. Even a careful painter can drop paint. Gravity wins. If only the ceiling needs paint, call someone who has done that without wrecking the walls.
The right colour
White is the usual ceiling colour. It makes the room feel taller and keeps the light. Unlike a wall, a ceiling rarely wants wallpaper, a busy pattern, or a heavy colour. A brushed decorative ceiling is possible, and it costs more because the work is harder. Dark, busy colours should be used carefully. If there is plaster detail, that gets a brush, not a roller slapped over the ornament.
Prep
Ceilings usually need less repair than walls, because people do not bump them. The top floor of a building is the exception: water leaks mean real repair before any paint. If you want the time and the budget kept under control, the prep has to be honest.