Step 1: Place your standing leg at a distance about 1 foot (20-30cm) from the ball
Step 2: Try to get enough room to swing your kicking leg, the more you swing the more power your Rabona should get
Step 3: Try to hit the ball with the point of the outside of your foot
Practice all three steps. First try to train without a run-up, after that train a good run-up.