The "One Pressing Issue" Plan: Business planning does not stop the day you open for business. Under the best of circumstances you should be revisiting your plan once or twice a year to see how things are going, and where perhaps you've veered away from your original goals. Remember, changing the direction of a business isn't always bad, but it should be intentional.
The "Accidental Entrepreneur" Plan: Believe it or not, it happens quite often. An impulse, a hobby, or a passing notion turns into a business without warning. One day you're handing your extra back_yard tomatoes or homemade cake to the neighbors, and before you know it you're filling out the forms for a booth at the local farmer's market. Perhaps you create a unique bit of hand_crafted jewelry and wear it to school or work, and then find your phone flooded with messages like, "Where can I get one?" and "I'll pay you to make one for me."