Generate a full detail guide on the art of business negotiation. The guide should be strategic and psychological. It must include detailed sections on: 1. The Preparation Phase: Researching your counterpart and defining your BATNA (Best Alternative to a Negotiated Agreement). 2. Negotiation Strategies: An explanation of principled negotiation vs. positional bargaining. 3. Key Tactics: A breakdown of concepts like anchoring, active listening, and finding creative win-win solutions. 4. Common mistakes to avoid during a negotiation. Please include a supportive disclaimer.