Business, sales and marketing guru specializing in creating innovative business strategy and setting up and managing sales teams. Key skill is understanding complex situations and breaking them into pragmatic action plans.
I'd develop Laurie's point. There are basically three questions you need your own great answers to. WHAT business are you in? WHO are your customers? HOW do you serve them with maximum efficiency? And as Laurie says, the answer isn't everything to everybody however they want it. Success lies in defining the tightest possible definition you can, that will be big enough to support the business you have in mind.
With those questions answered, the actual promotional tactics you use will usually be self-apparent.
Given the previous answers, I had to add my view. In my own case, I did an MBA late in life (I'd just turned 50). Now I teach part of the MBA programme at a management college.
Yes networking is a part of it, and I'm happy to introduce my students into my own network. But so too is the learning. Maybe the college where I work is unusual, but we put a big emphasis on entrepreneurial skills as a part of the MBA programme.
So it sort of depends on what you know now. If you need a thorough grounding in business, go get a Masters. Remember it doesn't have to be an MBA. An MSc in Management will cover much of the same ground, faster, and therefore at lower cost.