Focusing on your customers
Whether it is capturing that data in an excel spreadsheet, or an Airtable base or even a formal CRM software tool, tracking relationships and interactions with your customers is crucial.
Fail Fast - a real life story
Startups and established companies using the agile methodology have a mantra - "fail early, fail fast, fail often." I've been a big champion for failing fast over the years and I even won an "award" at a previous employer for failing during an innovation day.