Paint the two interior paint colors on scrap pieces of baseboard or crown molding to see how they look together.
Paint one wall surface a different color from a wall trim or crown molding. Match color families together such as browns with earth tones and aquamarines with cool tones.
Cover trim with masking tape and drop cloths while painting walls. Tape corners where the interior colors meet to avoid splotching of the different colors.
Paint large sections of the wall with rollers and paint corners with paintbrushes. Paint baseboards and molding with paintbrushes.