I typically prep by: * Clear the room of furnature. * Remove all wall plates and tape the switches & receptacles. * Remove heat & cold air return. * Tape the baseboards to paper or plactic. * Tape around windows and door trim. * fill then sand with a block, any holes or markes in the walls that you wish to cover. * Cover the floor.
Then to paint: * I start with a brush and do the corners around the ceiling. * If the ceiling and walls are different colors, you finish the ceiling first, then CAREFULLY cut a line at the top of the walls with a brush for the wall color. I don't worry about getting ceiling paint at the top of the walls and only cut once for the walls. * If the ceiling & walls are the same color, then brush all corners & edges prior to rolling. * Rolling should be the final step.
Remember to pour a small amount of paint into a paint pail when trimming and not to carry around the full gallon of paint. Accidents do happen, & I wouldn't want to clean up an entire gallon of spilled paint!!!!!!!
I like the plactic paint tray covers that you throw out for about 35 cents each. They are well worth the money.
Enjoy & Take your Time. Always use a DRY roller or brush, not a wet one that you cleaned. If you want to stop for awhile, wrap the roller or brush in plastic wrap to keep it wet with paint.