As humans we depend greatly on our hands. Our arms and hands are our first line of defense for balancing ourselves in everyday life. Instinct can take over and force you to use your hands for balance. Hanging onto the reins for balance is not entirely the fault of your hands because the hands only come into play as other balance mechanisms fail. The problem is inevitably elsewhere. You will not be able to develop good hands if you are experiencing balance problems elsewhere because as a human you will use your hands for balance.
Stop for a minute and think about what you are doing with your hands. The reins are an extension of your arms, the bit runs through your horse’s mouth. Next time you are on board make a conscious decision to be aware of your arms.