Whether you are stepping up to the plate to face a 95 mph fastball or making a sales presentation, confidence can make or break your performance. Your body language and your physical presentation have a lot to do with your overall success.

In sales, top performers find their enthusiasm and belief to be among their most important assets. If you're not at the top of your game already, use these four tricks to keep your confidence strong.

1. Be Prepared

The act of preparation itself can shift your attitude positively. The simple act of taking the pen to a pad of paper to write out your goals for a meeting--with a prospective or current customer, or even an investor--can move your attitude in the right direction.

Fear can be one of the most debilitating emotions--and simply focusing on meeting preparation can take your mind off worrying about what might going to happen. When you go into a sales call prepared and enthusiastic, you create your own mental confidence, imagining you've closed before you've even opened the door.

2. Get Smarter About Setbacks

Don't fear doors shut being in your face. Just as important as preparation is the action you take when faced with rejection. Setbacks, failed attempts, and lost business don't do much for your confidence unless you battle back and dig deep.

When faced with a "No," always ask yourself: What is this situation telling me? Do I need to call at a higher level? Find a more qualified prospect? Rework my presentation to fit the key needs of the customer?

Recreating your approach based on what you've learned gives you a better chance for success. This type of action teaches us how to work smarter and not give up on qualified opportunities. After all, landing the tough deals gives us extended confidence--and makes it easier to succeed the next time you face a similar situation.

3. Study Your Customer's Customer

When you are trying to learn critical information about your customer, you can learn more by trying to see though their eyes and understand their goals--and the goals of their customers. Think of yourself as an employee of your customer would, as if you were seeking new ways to grow the business.

When you understand your customers' business challenges and goals, and understand how your solution can help them, you gain tremendous confidence in your own approach.

4. Create Your Own Change

There are certain universal truths that create positive changes in our attitude, confidence and behavior. One critical one: As you think, so shall you become.

If you want grounded confidence that lasts, be choosy about the people and ideas you surround yourself with. Read material that will contribute to your personal and professional growth, and realize that the environment you create has a huge impact on your internal beliefs and performance.

Successful people have the confidence to take risks that unsuccessful people try to avoid. If you want confidence that stays strong in difficult situations, you need to change the ways you work and think.