Always make sure the paint is thoroughly mixed and follow label instructions. For interior painting allow for proper ventilation. For exterior painting, be sure to keep to the shady side of the structure and avoid painting when dew or condensation is likely to form, or when rain is threatening.
The right tools:
Brushes – use for trim, corners, and small areas. Synthetic brushes (nylon/polyester) are ideal for latex based paints. Natural fiber brushes (China bristle) are ideal for oil based coatings, stains, and varnishes.
Roller covers – use for large flat surfaces that are smooth or textured. Synthetic roller covers (nylon/polyester) are ideal for latex based paints. Natural fiber roller covers (usually lambs wool) are ideal for oil based paints. When choosing a roller cover, use a shorter nap for smooth surfaces and a longer nap for textured surfaces.