Nip it in the bud. If an employee has a complaint, listen. A supportive arm around the shoulder is better than fingers around the throat later.
Find a referee. If both parties are at loggerheads, an independent mediator can highlight ways for them to reach a voluntary agreement without any blood-spilling. They're cheaper and quicker than a tribunal.
Go to arbitration. In cases of unfair dismissal, an independent arbitrator offers a speedy, informal but legally binding alternative.