Matz shares six key lessons he learned from creating Ruby: 1) Don't ask for permission, beg for forgiveness later; 2) Don't value ideas alone, working implementations and community matter more; 3) Never give up and keep improving over time; 4) Appreciate the power of open source software and communities; 5) Pay attention to building and sustaining an engaged community; 6) Act like an amateur driven by passion, not money, to create great software. He advocates for an amateur approach to software development focused on continuous progress.