Not had it, but my daughter does so feel I can post here ;-)
My first thought was make sure that you have someone who can help out. Someone who is willing to take your dog(s) into the ring if you aren't up to it. Have a chair with you so that you can sit down, obviously :-) Make sure you have plenty food and drink that will give you a little energy boost. I found that having a crate for the dogs was a major benefit as we didn't have to worry about them pulling to say hi to their friends, both human and doggy :-p Let the steward know, if you do manage to go into the ring, so they can keep an eye on you.
These are all I can think of at the moment, but they helped me and my daughter out some years ago. If I can think of anything else (after speaking to daughter) I'll let you know.