Performance measurement: constitutes the last but not the less important stage of the marketing plan, since we can achieve only what we can measure. In order to measure the performances achieved through the marketing plan, we need to constantly monitor each previous stage of the plan.
You must know your competition in and out. Keep your friends close, but keep your competitors closer. You need to know all the things that you learned about your customers except fill in the blank for each competitor on all of those above items. Learn how you are the same/ different. Learn the similarities/differences about each product and service you offer. Learn how they sell or promote their products /services.