I actually have my students hit downhill shots quite often during lessons. The biggest adjustment is getting a persons lines (shoulder, hip, knees) to match the downhill slope. Once that happens, hitting shots from downhill lies is fairly simple. The added step that I add is is to have students walk through (step through) the shot with their trail side (right side for right handed players/left side for left handed players). This is a technique that I learned from Jimmy Ballard that he actually taught to Gary Player in 1978 to get rid of the duck hook. This is a great way for students to learn how the trail side goes down the line to the target and lends itself to striking very solid shots.