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.
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.