I follow a three-phase approach: Visibility → Accountability → Optimisation. First, I get full cost visibility by fixing tagging, setting up cost allocation, and building a reporting layer (typically Power BI) that finance, engineering, and leadership can all read. Second, I establish accountability by introducing chargeback or showback models, defining KPIs, and running regular financial reviews with each cloud-owning team. Third, I drive ongoing optimisation through right-sizing analysis, commitment planning (RIs, Savings Plans, CUDs), waste elimination automation, and anomaly detection. The order matters — optimising before you have accountability is a short-term fix that doesn't stick.