I am going to show you the key points for playing a shot from an uphill and downhill lie.

Uphill lie

The first thing you need to understand is how the ball flight will be affected by the slope and how the slope will affect your swing.
When your ball is on upslope the ball will go much higher and it will be more difficult to use your body. Depending on the severity of the slope will depend on how high the ball will go and how restricted your body movement will be.
Below are key points and photographs to help you when playing from a uphill lie

• Club selection.  If the distance suggests that you should take 8 iron then I would take 7 or 6, this is because your swing will be limited by the slope as will your balance so you don’t want to be swinging too hard. The ball is also going to go more upwards than forwards thus resulting in a shorter shot so make sure you take more club.
  

• Set up.  Play the ball a little further back in your stance than normal and make sure that your shoulders are on the same angle as the slope. The feeling should be that you have more weight on your lower foot (right foot for right handed golfer).
  

• Swing.   A controlled three quarter swing with no more than 70% of your speed is what is required for the shot. The harder you hit the ball the higher it will go thus resulting in loss of control.
  

Downhill lie

Physically this is a much more challenging shot, especially for ladies and juniors. This is mainly because a downhill lie will produce a much a lower ball flight so we will usually try somehow to help the ball in the air which on this shot especially will result in poor results.
Below are key points and photographs to help you.

• Club selection.  It depends on how severe the slope is but as a general rule you want to take one club less than you normally would. The ball is going to go lower and further. For high handicap golfers I would suggest no more than a 7 iron.
  

• Set up.  The ball should be played further forward in your stance with at least 70% of your weight on your front foot (Left foot for right handed golfers).
  

• Swing.  You want to have the feeling that you will swing a little steeper than normal on the back swing and then really feel that on the downswing you will swing down the slope.