 Begin painting at the top of the house and work your way down. If you're painting horizontal siding, coat the bottom edge first so you're less likely to miss it. You'll also want to feather or fan out your brush strokes so that you can eliminate overlap marks and drips. If you have a large area to paint, you might consider using an airless sprayer. Keep the sprayer moving in steady, even strokes to avoid buildup and have a brush ready to back brush