You will need to develop or define important information about your company. In your business plan, you should have developed a Mission Statement, a Vision Statement, and a Culture Statement. If you did not develop these three items, you must create them immediately before continuing onward. It is vitally important that everyone knows about and buys in to these three company statements with all employee staff so that every person inside the business will communicate these items correctly to all external people outside of the business. You want their belief and confidence as high as the owners or top executives.
Corrective Plan. A marketing plan is a living document. Trust me, the moment you have it and experience planning your marketing, you will realize this. Therefore it is a plan that allows you to assess past strategies and results and at the same time allow you to make necessary corrective measures to fit your business growth. for example, who expected the 2008 financial crisis to hit us so badly? No one other than the few so called "economists" but how did responded to it? Severely. Many businesses closed including many giants. But the good thing is, many have a solid marketing and business plans, therefore they make quick corrective actions and moved forward.