When I ask entrepreneurs and small business owners, it is not unusual for not having any marketing plan. I once read that Sir Richard Branson never had any marketing plan when he started the 1st Virgin business many years ago. In fact in one study of entrepreneurship (I couldn't recall the name of the study) was that as much as 50% of entrepreneurs and business owners don't have a business plan and marketing plan when they first started the business.
Ideas _ people said the more you talk about your ideas the more refine it becomes. I think this is true. Did you ever experience when you talk to more people you generated a lot more ideas? When people give you feedback it triggers another dimension of your ideas? If you are, so where do you keep all these ideas? It should be in a marketing plan.