Repair window casings, door frames and gutters as needed. The fresh paint will get scuffed and damaged if you wait to finish repairs.
Remove any old, flaking paint. Wood should be lightly sanded. Plaster and cement can be scrubbed with a wire brush.
Clean with a mild detergent and water. Let everything dry completely.
Patch any cracks or holes. Use caulk to seal cracks around doors and windows. Use spackling paste for holes or chips in walls.
Protect the areas where you will paint from spill and splatter. Use drop cloths to cover floors, porches and walkways. Use painter's tape for tight areas around doors, windows and woodwork.
Prime any surfaces where old paint will be covered. Primer will help the new paint stick. Let the primer dry completely before you paint over it.