The key to success with a downhill lie is understanding that the ball flight will be lower and the ball will roll out more when it lands.
That said, it is essential to select the right club.
Remember: Less loft means more distance.
ALIGN YOUR SHOULDERS PARALLEL TO THE HILL. This is key to avoid scooping or thinning the ball. Play the ball slightly back of center.
SWING DOWN THE SLOPE with smooth acceleration through impact to avoid coming out of the shot.