And with just a little more data you can actually determine how many customers you would need for each year you plan for and how many leads you would need. From that you can actually determine what size market you would need and whether your market is big enough to supply those leads that could be converted into customers.
Developing Planning Modules: Compartmentalizing your plan by developing planning modules or "chunks" allows you to attack the plan in parts, yet still maintain a cohesive plan. I have found that developing an annual plan made up of quarterly targets _ thus becoming a rolling quarterly forecast financial model _ allows for a cohesive structure along with the nimbleness to react to market conditions. At the end of each quarter, a true_up process to align results to annual targets needs to be re_forecast and adjustments made.