If the ball is above your feet at address, you will want to set up with a more upright spine angle than normal. Also, make sure to set up farther from the ball and aim a little right as well.If the ball is below your feet at address you will want to tilt more at the hips so that your spine angle is more bent over. Also, make sure to set up closer to the ball and aim a little left of your target.
The best way to practice these shots is to play 9 holes late in the evening when the course is empty. Every time you come to an awkward stance just hit 3 or 4 balls from that spot. Hitting on the driving range is great, but the tee box is always flat. If you get out on the course by yourself make sure to practice those shots from uneven lies.