A marketing plan is what lets you tell, at the end of a month, which thing actually worked. Without one you are spending in several directions at once and cannot separate the effort that paid from the effort that did not.

Written down, it also survives a slow month. Undocumented, the first quiet week turns into starting over with something new.

Three things, and the plan is thin without any of them:

• Your target customer sentence from the earlier step
• A monthly figure you can genuinely afford, even if it is zero and the currency is your own hours
• An honest list of what you have already tried and what came of it

That third one is the most useful and the one most people skip. A plan that repeats a failed tactic is worse than no plan.