Failed CGC once, retaking next month — what actually helped you pass?

So I took the Canine Good Citizen exam back in March and my dog Biscuit completely lost it during the "reaction to another dog" exercise. He's a 3-year-old rescue mix and I thought we were ready, but apparently not. I've been training consistently since then and I think we're in a much better place, but I want to make sure I'm not missing anything on the knowledge side too.

I've been going through a CGC practice test online to refresh myself on what the evaluators are actually looking for in each exercise — I didn't realize how precise some of the criteria are, like the exact distance requirements for the walking exercises. My trainer suggested I also read the official AKC study guide, but honestly some of it is pretty dry and I'm not absorbing it well.

Has anyone else failed and come back to pass on a retry? I'd love to hear your exam tips, especially for the more behavioral exercises. We test June 14th and I really want this to be our moment.