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.
Marketing Plan: In this you perform, precise activities which helps in achieving the goals and objectives you are targeting at. Here, you plan how you will promote the product/service? What are the specific areas of promotion? What would be the budget of this plan execution? Etc. Plus, you also estimate the ROI of this marketing strategy.