This provides the overall direction of the company by establishing high-level goals that will be achieved by tactical initiatives. The overall plan should be 1 to 3 years with measurement mileposts monthly, quarterly and annually. While the plan is put in place at the onset of the year, it should be constantly re-forecast with actual results throughout the year.
New businesses have a greater challenge - they will rely more on market research using libraries, trade associations, government statistics, surveys, competitor observations, etc. In all cases, make sure your market analysis is relevant to establishing the viability of your new business and the reasonableness of the sales forecast.