My first step would be to take advantage of some of the tax dollars you've already paid by paying a visit to the Small Business Administration.
They have many pamphlets and booklets available that can help you in getting started, and they have advisors available through the SCORE program (Service Corps of Retired Executives) that can help you navigate the waters of getting a business license, setting up your records system, incorporating if you choose to do so, etc.
HTH.
Yours in Budo,
---Brian---