Dear, my husband says, did you use a light weight spackel to fill the holes and any cracks in the walls? Then you have to sand and touch up the texture with a spray texture.  Always know that drywall is imperfect and will show flaws so you need to understand paint sheen.  Flat, Eggshell, Satin, Semi-Gloss, and Gloss finish the more sheen the more imperfections you will see.  Eggshell is my recommendation for walls and flat for ceilings.  Now, tray ceilings are a great accent and can be done either way, according to taste.  Lighter than walls produces an open more airy effect, darker will bring down high ceilings making the room cosier and more colorful.   OO0H! I say.