3. Don't ignore your customers. This may sound obvious, but too many entrepreneurs assume they know exactly what their customers need without bothering to ask. Take the time to learn about your customers, and build your business plan around their needs and desires.

4. Don't shortchange the competition. If you assume your firm will be the only game in town or if you fail to take existing competitors seriously, you're asking for trouble. Your competitors can be a great source of information about what works and what doesn't.

5. Be prepared to take risks. Creating a business plan isn't about avoiding risk; it's about understanding and managing risk. That's why a good business plan anticipates possible challenges and includes a variety of scenarios for meeting those challenges. There's a difference between a calculated risk and recklessness, and your plan can help you make that distinction.

6. Get a second (or third) opinion. The most experienced entrepreneur can still benefit from a different point of view. Even if you're the only person involved in your business, find someone who can study your plan objectively and point out possible weaknesses you might have missed.

7. Expect the unexpected. Every business plan needs some wiggle room to allow for unexpected changes. Part of this involves creating budgets and marketing plans with some built-in flexibility; but adapting to change also requires you to accept that you might have to modify or even abandon business practices that worked well in the past.

8. Don't forget what makes you unique. A cookie-cutter business plan might help you get started, but it won't help you succeed. And while it helps to look at your competitors, don't model your business after them. After all, you're in business to beat the competition. Learn from your competitors' strengths, but also learn how to spot their weaknesses and use them to improve your own business plan.

9. What's the point? Building a business involves hard work and struggle. But it should also include a clear set of rewards, both for you and your employees. When you set goals in your business plan, include some concrete motivation that goes beyond the satisfaction of a job well done.

10. Don't skip the plan! Of course, the biggest mistake of all is failing to create a business plan in the first place. Planning is hard work, and there's no guarantee it will make your business succeed. But a good plan is still the best way to turn your vision into a realistic, coherent business.