Well as far as having your animal judged its mainly about how well bred your rabbit is. ARBA standard is what most people go by now a days, but it can be different for meat breeds as they can be bred for show (ARBA standard) or for meat. Now as far as it goes for planning to enter your rabbit for said shows you can do some things, such as cleaning/conditioning your animal/s. You want your rabbit to have good coat condition, well filled out but not overweight and proper kept nails to name a few things.
Now when you are looking into table top showing, which in conformation showing you may have to do anyways, you should know these things:
-You should know the anatomy of your rabbit. This means if the judge asks you where the rabbits such and such is, you should know, and show that part to your judge.
-You should know your breed. This is very important. Knowing your breed of rabbit and what purpose/s it's bred for shows you know what you are doing
-You NEED to know the gender. I can't stress this enough! I have seen kids go into a class thinking they have a doe, only to find out they have a buck in the wrong class (and vis versa)
-Age is important to know. Anything under 6 months is junior, over is senior. If you have your rabbit in the wrong class, it can hinder your animal placing.
-Finally you need to know how to handle your animal. This means knowing how to properly pick up and point out parts of the animal. This also means you need to know how to set up your rabbit. Each breed is set up a certain way, Hollands stand very upright where as mini lops have a very down hill pose. (just to name a few)
All of these things make for a successful showing with your animal.
Hope that helps you out!
Also Id check out this site,
https://www.arba.net/