Mouth closed, ears open (edit: people will be talking strategy, listen to them, or watch them as they look at the course) . Otherwise, don't be afraid to ask questions. Just have fun for the first time though. Don't get bogged down trying to overthink it.
One thing I would ask is: How is the target scored if you fire more than the prescribed round count. Where I played, it was the best 2, if it was a 2 shot string. I missed out on a lot of points when I knew I slung one a little. I could have fired another round and run 'perfect' runs. I don't know enough about the actual rules to know if that was a local thing or actual rule for IDPA. I'll probably dive deep into the rules next year when I no longer have a badge and the time constraints that go along with it.
Again, stay safe, have some fun, push yourself a little. Life's boring when you're comfortable.