Although event sourcing (and its sister pattern CQRS) has been gaining traction in recent years, it's still baffling for many engineers attempting to implement it for the first time. While there's plenty of material on the subject, most of it is too basic or theoretical for practical applications, and engineers often end up having to reinvent (or rediscover) suitable approaches and techniques. This talk focuses on practical aspects of building event-sourced systems, lessons learned from our experience building such systems at Wix. We'll walk through the design and implementation of a relatively simple event-sourced system, covering the event model, underlying persistence model, code layering/factoring and operational considerations. A talk given at Reversim Summit 2017 in Tel-Aviv, Israel.