I only have experience with Maia so I'll share that.
First of course rabbits must not be starved before the op, they must be allowed to eat up to the last minute but I'm sure you already knew that.
Prepare a carrier with a fleece blanket in it for the bun to recover. She will be very groggy in the beginning and she might take a while to wake up. After GA, she will not be able to control her body temperature well so you should provide a heat pad, warm water bottle or something similar, especially if her ears are cold at the touch.
Ask your vet for pain relief. Especially in the first 2-3 days, your doe will probably be in pain and if she is, she won't eat. So pain relief is important.
When she wakes up, you can put her in a cage and leave there for a week or so so she won't open her wound again. She should not have the chance to climb, jump or make efforts.You should remove loose bedding (i.e. megazorb) and replace it with something that won't stick to the wound such as newspapers or the like.
Maia had a big patch over the wound so there was no chance for that to happen, but I seem to understand that not all vets in England use it.
There's a chance that the doe will want to pull her stitches. To prevent that, you can ask the vet for a collar. It prevents rabbits from eating caecal pellets though, so it should only be on when you can't keep an eye on her, i.e. at night. Maia's collar was too large for her so in the end she had pulled all her stitches! Luckily by then the wound had healed and it didn't open again. But some does pull their stitches on their very first day and as you can imagine, that's dangerous.
Your doe might not eat straight away. If she doesn't eat for more than 6-10 hours after waking up, you should prepare some liquid food like Critical Care (ask the vet for that) and syringe feed her. You need to be extra delicate because of the wound. With some luck and the help of pain relief and something the rabbit likes, like parsley, you won't need to do that, but be prepared.
Finally, I encountered a minor problem that nobody had told me about.
When the would closed, Maia had a hard raised lump on her belly, about the size of a finger. She didn't appear to be bothered by it and it was hidden by the fur, but it could be felt very well at the touch so I was a bit worried. The vet told me it was normal (can anyone confirm that?) and that if it didn't reabsorb in 2 weeks, I should bring Maia back to her. Luckily, after a while, it disappeared on its own.
I think it's all I know! Good luck with your bunny being spayed. In a few days she'll be OK again!