Choose two or three colors of paint or stain that look good together and are a good fit with other colors in the area you will place the bench.
Place your bench on drop cloths to protect the surrounding area. Gently sand the bench to remove any old paint or finish. Dust well to remove powder.
Start with the darkest color. Dip the paintbrush into the paint just enough to wet the bottom 1/2 inch of the brush. Apply with quick strokes to the bench, making sure all strokes go in the same direction. Do not worry about perfectly even coverage, or even missing spots.
Wipe the freshly painted surface very gently with a clean rag as soon as you finish the first coat of paint. Wipe in long strokes all going in the same direction, without going back over an area once wiped. Do not circle or rub with the rag.
Let the bench sit for several hours or overnight until dry.
Apply the next color of paint. Dip just the paintbrush tip into the paint, leaving the brush mostly dry. Paint in even strokes going the same direction over the bench, without worrying about fully covering the bench, or leaving any missed or bare spots.
Wipe with a clean rag as soon as you finish the second coat. Wipe very gently, with all strokes going in the same direction. Do not rub or circle with the rag.
Allow bench to dry for several hours, or overnight. If you plan on painting with a third color, follow the steps given above. Let dry completely for 24 hours.
Sand the edges of your bench with fine grit sandpaper. Sand places that would naturally be worn by use, such as the front edge of the bench seat, and the top and front of the arms.
Dust the bench thoroughly, then spray with several coats of polyurethane furniture protector. Let dry as directed on can before using the bench.