How to Load a Brush
Dip the brush only about a third or halfway into the paint. To avoid dripping and keep your fingers clean, do not sink the brush up to its metal ferrule.
Let excess paint drip for a moment, then lightly tap both sides of the brush against the interior wall of the can or bucket. Scraping excess paint on the lip of the can is messy and counterproductive because it removes the paint you just loaded into the brush.
As you paint, make sure to keep a wet edge, and continue to paint from that point forward. Use long, smooth strokes and refill the brush whenever the paint starts to break up without covering the surface properly.
Note: The bigger (and thicker) a brush is the more paint it will take to the wall. A beginning painter may want to start with a smaller brush. A thin angle sash style brush is a good choice for practicing precision painting.