Devote the same care to choosing your brushes as you do to picking your paint.
Many people get confused about which bristle material to use for various paints.
Natural-bristle brushes behave the same way in water, which is the base of latex paint. A frizzy brush does a bad job, so save natural bristles for oil-based varnishes and paints. For latex paint, you need synthetic bristles, like nylon or polyester. Unless you clean the brush very thoroughly, you'll contaminate your paint and spoil the finish. Paint com es in sheens from flat to gloss, each with different practical benefits and decorative uses.