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.
When you, and your partners if any, have all the core skills and industry knowledge you need to start right away without seeking experts, napkin notes may be enough to get going. Let's say you are already an expert in technology and social media. Then you, and your team, probably don't need a detailed plan to start developing a new app. You will draw on your knowledge and experience, and you understand that you might need to go back and do some more detailed and formal planning later. Certainly when you reach the point where you are looking for investors or lenders, you will move beyond those first casual notes. Until then, drawing upon your expertise can allow you to quickly jump into the market and perhaps gain a competitive edge by using a minimalist plan.