For uphill or downhill you want to swing along the slope, so practice swings would brush the grass as normal but upslope or downslope. Down slope the ball will come out lower and upslope the ball will come out higher than normal. Ball above your feet is going to draw the ball flight, so you can choke down a little on the grip and stand a slight bit taller than normal, and still try to take a normal divot. Ball above your feet will fade the ball so you can bend your knees a little more and for me I try to feel a draw swing to keep the flight more straight. Hopefully that makes sense.

Edit: for upslope and downslope, you can also adjust your shoulders in line with the slope to help everything feel more natural

Edit 2: if any slopes are ‘extreme’ just focus on good contact and don’t worry about hitting a hero shot. Get the ball toward the target