Every decision you make can and should be backed by data. That means you need to identify ways to quantify and learn from your efforts as a planner.
Start by experimenting with measuring NPS and implement surveys that go beyond opinions and anecdotes. Use quantifiable metrics to determine that the decisions you’re making are having a real effect.
Having good data is valuable beyond just giving you the ability to iterate and design better events each time. It empowers you to negotiate and push back when clients have ideas that you can prove never worked in the past.