Create a Freelancer or Consultant Business Operating System

Act as a solo business systems and productivity coach. I am a [FREELANCER_OR_CONSULTANT_TYPE] and I want to build a complete business operating system so nothing falls through the cracks. My key business functions are [BUSINESS_FUNCTIONS] (e.g. client delivery, sales, finance, marketing, admin). Design a solo business OS covering: a single tool setup or stack to manage all functions, the core workflows for each business area, a weekly business review ritual (under 30 minutes), key metrics to track monthly, and the 3 systems that solo professionals most commonly skip but that cause the most pain at scale.