Which advice would you give to someone who has just been diagnosed with Adrenal Insufficiency?

Stay on top of this disease! Know what the symptoms of a addisonian crisis are.

Knowledge is power but do not maudlin about things, as soon as you know the facts of what it is, how it can affect you and what to do in an emergency, just get on with life, it is only a label !

If you have been diagnosed: Congratulations! The road to being diagnosed can be (and usually is) very long and scary. Answers are a good thing. Learn all you can about this disease while you rest and heal. Be kind to yourself and remain hopeful, it does get better. Play your part in spreading awareness. It can take some time to get yor replacement hormones balanced and to learn about up dosing, stress dosing and when to inject to avoid crisis Ensure you have a knowledgeble and supportive medical team. Wear a medic alert bracelet or chain. Carry an emergency injection. Seek help if you are ever in doubt. Now go! Live! You have a new lease on life!

Ask Doctors, "What experience do you have with this disease? How many patients have you treated with it? Are you willing to learn and work with me as an individual to provide the best possible quality of life?" And learn how to advocate for yourself. Always take someone close to you with you to be a support and validate your concerns.
I found many endocrinologists have never had a patient with AI because it is rare. Many just do not know how to properly test for it or treat it. Because of this, many in our community deal with improper care that can lead to crisis and distrust with the medical community. Finding the right doctor is trial and error. But keep looking and reach out to your community and support groups for recommendations on area doctors.