This document provides lessons learned from using engagement tools at over 10,000 events with 3 million attendees. It discusses why engagement is important for effective learning. Traditional lecture-based learning results in only 20% knowledge retention, while active learning approaches lead to 70-90% retention. The document outlines common barriers to engagement, including attendees not participating, presenters not adopting tools, and a lack of follow-up after events. It provides tips for improving participation, such as incentivizing and gamifying engagement. It also suggests educating presenters on the benefits of tools and requiring them to address questions after events. Measuring engagement goals and using data to improve is also recommended.