Good preparation: wash the walls, especially in the kitchen, lightly sand if necessary. Use good primer as a basecoat. Some people paint trim first, some paint it last. Trim paint is different that wall paint. Use kind of latex paint that you can wash. Tape windows or glass. Don't paint over light switches or outlet plates--remove them .Wipe upspills immediately, don't try to move a ladder than has a paint tray or bucket on it--it will fall!!! If you want to take a break,put the brush or roller in a plastic bag in the freezer--make space there before you start. Do use liners in your paint tray for a roller. Check that each can of paint is the same color. Stir paint often. Wrap plastic around the hand set of your phone before you start, or wear vinyl or latex gloves. If youdon't like the color after you have painted pone wall, you will really hate it after you have done the whole room. Painting isn't rocket science; he can do this. Some hands are steadier than others, if in doubt--tape it off! And blue tape needs to come off within 24-48 hours or it becomes like glue, and is very hard to remove.