I commend you for making the effort to write for a judge at a rabbit show because it's not for everyone. Writing for a judge can be a lot of fun, but it can also be very stressful depending on the judge and the exhibitors. I've taught many writing clinics to youth and adults, and the following is what I tell them to make the experience as good as possible for the writer, the judge, and the exhibitors.

Talk to the Judge and Exhibitors.
Let the judge know ahead of time that you are doing this for the first time. Let the exhibitors know this, also. I always tell the exhibitors, "Well, guys, listen to the judge's comments because this is my first time and I may miss something." They should be present and listening when the judge is there, anyway.

Familiarize Yourself with the Comment Cards.
Before the judging starts, it's a good idea to look over the comment cards. That way, you'll be able to write down comments in the appropriate places quickly.

This is what an average comment card looks like.

Gather the Comment Cards.
When the judge starts looking at a class of animals, I like to gather the comment cards for that class, writing down how many rabbits are in the class on the cards and arranging the cards in a staircase stack, so that the ear number shows. Then I stand aside and let the judge look at the rabbits. The judge will let you know when he/she is ready to comment on a rabbit.

Jot Down Important Comments.
When the judge is ready, he/she will tell you the ear number of a rabbit and what the rabbit's placing is, and then he/she will start rambling about the rabbit. Try to get down the important comments like long in type, good head, flat over the HQ, nicely balanced, very promising junior, snipey in the muzzle, ears too long to balance, etc., and any reason for a disqualification (DQ) such as unmatched toenails, white toenail, butting/trapped teeth, broken tail, missing testicle, etc.

In Some Cases, Write as Many Comments as Possible.
Some breeds have a lot of points for markings or fur. For these animals, you really need to write down as many of the judge's comments about those areas as possible. This way the breeders know where the trouble spots are in their rabbits.

Oh no! I Missed What the Judge Said!
If the judge says something and you didn't hear him/her, don't be afraid to ask what was said. If the judge goes too fast, ask if he/she wouldn't mind going a bit slower than usual for the first few rabbits so that you can get the hang of the order that the judge goes in. Most will always start off in one area such as the head or the type. Judges will usually slow down for you because they can't go on without a writer, unless they wants to write the comments themselves.

The Exhibitors Are Complaining About My Writing!
If anyone complains about you missing comments, simply tell them, "I"m not perfect, and if you can do a better job, then do it!" I know it sounds mean, but not many people want to do the job in the first place, and therefore they shouldn't gripe at the person who is willing to do it. If they wanted all the comments, they should have been there, listening to the judge give them. A comment card is only there as a reminder of the rabbit's placing and some comments given by the judge.

If an exhibitor gets too abusive, let the show superintendant know, and they will deal with the person.

You'll Get the Hang of It.
After about 10 or so rabbits, you will probably have the hang of it and write comments like a pro. Don't forget, practice makes perfect! By, the way, I still make mistakes or miss something, and I've been writing for years.