Here are a list of advanced balance exercises you can do. These are progressively harder and will take time to master. Go slowly. The advanced ones, such as standing up on a swiss ball, are potentially dangerous.
Balance is really important for all aspects of life and sport. The more you practice, the easier it gets. All levels or balance, from really shaky on up, can improve and benefit. Balance, an autonomic system, is controlled by your inner ear, vision and proprioception (feeling of space in your limbs and muscles).
Balance exercises are also a lot of fun.