To make an effective plan, there is a famous rule called 4P's. Here, P's stand for Price, Product, Promotion and Placement. In this another P is added called People. Today while doing digital marketing or the traditional marketing one should understand people or the customers you are dealing with. It's important to figure out what is significant for the business, and later make a plan accordingly.
Guide _ in a marketing you will think, record and document all your ideas, products and services offering, price, distribution channel, programs, sales direction, customer segment and so on. I have experienced whereby I suddenly realized that my business is not going on the right direction because I didn't follow my marketing plan. Have you experienced that? Or perhaps you suddenly realized that the thing you do know supposed to be done many months ago because you forgot about it? And you forgot because you don't jot it down and plan for it? This is what I mean that marketing plan as a guide. I cover this in my Marketing Plan Breakthrough S6PEC.