So, at least a couple newly minted RO's, huh? Congratulations, and thank you for taking the time and effort to become certified. You'll be assets at any match you shoot, and I look forward to shooting with you and assisting in any way I can, if ever needed. Here are a couple thoughts from my personal experiences, if I may:
Use what you've learned and always be open to adding to it. Like with most things, you'll be more comfortable the more you do it. Don't be afraid to admit you don't know something or that you may be wrong, but also don't be afraid to stick to your guns, so to speak, if you feel like you are right. It's all about safety, primarily, and fair application of the rules so that everyone can enjoy their match experience.
When it comes time for renewal, take the online "short test" within the time frame given. It's not bad compared to what you just took and is not much of a hassle. If you wait too long, you'll have to take the "long test" which is more of a pain. Wait long enough, and you actually have to take the class again.
Lastly, if you have the interest, you can go farther with your certifications. I took the Level II class several years ago and it was pretty good. It is more about stage design and safety while Level I is about running shooters through the stages safely. I've never taken Level III so I can't speak to it. Just depends on what you want to do with it and how far you want to go.