Forget the sidehill part for a moment. Keep it simple. You have uphill lies, and downhill lies. The most significant elements of those two differing lies requires two things: (1) Setting up WITH the slope of the ground (in other words, keeping your shoulders level with the slope of the ground). (2) Thoughtful consideration of club selection.

Typical downhill lies normally require less club. Why? Because the angle of the slope that the ball rests on isn't flat, and the angles change. Your center of gravity changes. That's is why you should always play downhill lies further back in your stance, to account for the difference in your center of gravity (or the bottoming out point in your swing). And generally speaking, you should take less club, once again because of the angle at impact. A typical 8iron that impacts the ball on a downhill lie actually has the effective loft of a 7iron, or maybe even a 6iron depending on the severity of the slope. And remember, if you're setup is proper, your shoulders will mirror the same level as that of the slope you're hitting from.

Uphill lies -- one concept stays the same -- your setup. Shoulders level with the ground. The other concept is completely different, however. Your ball is sitting on an up-slope, not a down-slope. The 8iron example I used earlier -- with this lie, the effective loft with this shot using an 8iron is more realistically the loft of a 9iron (maybe even a wedge, depending once again on the severity of the slope). That means less distance, because the club is already impacting the ball at a higher loft angle.

So in essence, the uphill-downhill lie revolves around distance and proper club selection.

Now the sidehill part. Sidehills do not have nearly the impact on distance, but more on direction. Sidehill lies where the ball is below your feet -- expect the ball to fade (or slice). Factor that in with your setup, and account for more left-to-right movement if you're a righty, and right-to-left movement if you're a lefty. The amount you open your setup to account for this naturally depends on the severity of the slope. The more sidehill the lie is, the more you should open your stance to account for it.

If the ball is above your feet, do the exact opposite of what you would do playing the ball being below your feet. You actually close your stance, as opposed to opening it, to account for the right-to-left movement for righties, and left-to-right movement for lefties. Once again, the more that the ball is above your feet, the more you need to account for movement.

In both instances, club selection is vital. But looking at both concepts individually (uphill versus downhill) and sidehill (ball above your feet or below it) helps keep things simple. One has more of an influence on distance, the other on direction. Applying these concepts together should help you figure out what to expect, and how to account for them.