State education finance systems play a fundamental role in providing the resources that schools and districts need to ensure student success. But modernizing and improving these systems is often complicated and can take years. Learning from their efforts to revamp education finance systems, Bellwether has found five common conditions that pave the way to success: (1) strong, diverse coalitions; (2) willing political champions; (3) rigorous, accessible research; (4) windows of economic opportunity; and (5) valid legal challenges. This policy playbook builds from that five-condition framework and offers more concrete guidance on how advocates, policymakers, and education leaders can influence K-12 funding reform in their states. It contains guiding principles to help stakeholders identify policy priorities and opportunities. It also offers guidance on how to assess and strengthen the state's readiness for change, including a checklist of questions, potential pitfalls to avoid, and examples from other states.