Work From a Paint Pail
Rather than dipping your brush into the gallon can the paint comes in, transfer a small amount to a paint pail. Pour only about an inch of paint into the pail. A small amount of paint prevents dipping your brush too deep, reduces weight and expedites cleanup if you spill the paint. You can buy special plastic paint pails with handles built in or a metal one like the one shown here. An empty paint can with the rim removed also makes a great paint pail. You can remove the rim with a kitchen can opener.
Pat, Don't Wipe, to Load the Brush
Dipping the paintbrush and then wiping off the paint on the edge of a bucket is a common practice, but it's not very efficient. It's better to leave more paint on the brush by dipping the bristles about an inch into the paint and then just patting the brush against opposite sides of the pail. With that amount of paint on the brush, you'll be able to cover more surface before you need to reload.