There are some thinks you can do to improve your game. During the jump you can arch your back to make your stomach face the sky. Dot his whilst you're in mid air jumping over the pole. Then use abdominal muscles and arch your back, and then curl yourself back up quickly. By perfecting this move you can ensure that you don't injure yourself, you go over the pole without touching it and you land properly afterwards.
Playing basketball can help to. Basketball players need to run at angles that create a good lay up technique. This very same running and jumping movement will be used when you do high jump. You will need to practice this so that you can position your feet properly, so that your ankles are able to lift you off the ground as effectively as they can.
Using balance beams at the gym will help you too. This allows you to find your own center of gravity, which means you will know where you need to focus all your energy to get over the beam. The technique allows you to improve your game but it also allows you to avoid obtaining injuries during the process. You need to practice the high jump before you enter competitions. After just a few practices you will see what needs improving and once you've been able to do this then you will be able succeed in competitions.