All courses have elevation changes on them to a certain extent so learning to play great golf shots when faced with such changes will really help you shoot a low score.
If you find that you are playing shots to an area lower than the golf ball is being hit from, then the golf ball is going to stop very quickly when it lands as it will be dropping from a more vertical position than usual. The ball will also be in the air for longer than usual so it will have an extended flight and as a result, it will fly further than usual so play the shot with less club than you would usually use. Instead of playing a 7 iron, for example, play with an 8 iron as the ball will fly further in the air than usual.
If you are playing to an area lower than you are hitting from and you find yourself playing the shot from a downhill slope, then you also need to make some adjustments to your set up position. When playing from a flat lie, your spine is perpendicular to the floor so your need to recreate this spine position even though now you are on a slope.
To do this place your weight on to your lower foot and tilt your spine over until your shoulders reflect the angle of the slope and your spine is perpendicular to the floor. The slope will also affect the way that you swing the club so you need to play the ball more towards your higher foot than usual and swing with the slope. Furthermore, remember that playing from a downhill slope will result in a lower ball flight than usual so play with a more lofted club and also the ball will fly left to right in the air because of the effect that the slope will have on your swing, so aim more to the left to allow for the fact that the ball will swing right in the air.
If you are also playing from an uphill slope, again adjust your set up so that your spine becomes perpendicular to the floor. Place your weight on your lower foot and tilt your spine over towards your lower foot until your shoulders are parallel to the slope. Again, because of the effect that the slope will have on your swing, play the ball towards your higher foot and swing with the slope. Your shot will fly higher than usual and also right to left so aim to the right of your target to allow for the fact that the ball will swing right to left in the air.