If you're going to do any part of the painting or prep work on your own, you must know that the first step in preparing a surface is washing it. Since dirt can affect the smoothness of a surface area -- and therefore paint's adhesion to it -- use soap to remove any dirt or stains. Make sure there's no soap left on the walls when you're finished; also make sure to remove any gloss with sandpaper and vacuum up the leftover dust.
Any of these primers may be used, depending on the conditions required on your home. Oil-based primers soak into new wood better and are also used on rusting areas, such as around gas meter, prior to painting. Oil-based primer works better in keeping steel gas meters and other steel surfaces from rusting in the future. Notice the amount of white primer in Figure 3, that Scott's Painting & Staining Inc. applies to give a professional looking finish. This photo also shows the efflorescence coming out of the concrete block foundation that was scraped off and treated with a Concrete & Masonry Primer designed to help control efflorescence.
When painting the trim, you don’t have to be neat. Just concentrate on getting a smooth finish on the wood. Don’t worry if the trim paint gets onto the walls. You’ll cover it later when painting the walls. Once the trim is completely painted and dry (at least 24 hours), tape it off (using an “easy release” painter’s tape), then paint the ceiling, then the walls.
A good contractor doesn’t just do quality work, of course. Workers should be courteous, pleasant, and capable of clear communication. Ideally, the people altering your home’s look will be enthusiastic about the task rather than jaded and burnt out. Find out from your references what kind of attitude the company’s workers displayed, and whether they behaved professionally. Also ask whether the crew stayed on schedule, and whether they arrived early each day, did their work, and got out of there.