It's hard to imagine a house that does not need to be washed down prior to painting. In the most of painting projects, I still recommend washing down the house.
Scrape or sand the paint down to the bare surface Remove all peeling paint. You scrape that little dime-sized flake of paint, and it leads to more and more and more... If the edges of the paint will stay down, leave it alone. The new paint will seal the edges and keep it down. It's not a perfect seal–never will be–but it will hold for awhile. Prime the surface with a quality latex primer, prime only problem areas, not whole house and let it dry completely. Apply a quality paint in the desired finish.
Check around all doors trim, window trim and corner trim find where old caulk in cracks and caulk it.
Mask all the window, doors, concrete,roof. Spray Large Featureless Areas. After that paint the trim with roller and brush. Check the house for touch-up