Looking back I have a few things that I would change.
Location, location, location- We did of course move the rabbits to a better spot with more shade and better weather protection. Knowing what I know now I would have started there, but putting them in the garden with the ease of moving poop around less made more sense at the time. We bought a great yard cart so that eased the transport situation. So lesson here is to start it right.
Replacements- There are a few rabbits that I wish I would have kept. I had some great Silver fox does out of Hoshi and Galaxy. At the time I was trying to wean my numbers down. It is tricky on its own to try and manage space/rotation for rabbits and kits. But then adding in space for replacement stock is even more so. Some went into the freezer that I should have kept. So now when I run across one that is good I hold it back. If I find that I have done that too often then I can always sell it. I did that with Yahtzee and her brother. I kept her and sold him (I always too many bucks).
Mark the date and learn to palpate- A sad thing happen in March. I had put Panda in with Wasabi during the breeding for 3 other does. As far I I saw she hadn't lifted and I hadn't seen any falloffs. I am also not good at palpating so I thought she wasn't pregnant. When I put nest boxes in I often give a little treat hay (I know I don't do a lot, but they all start making such a noise that I do for those few days). She never made any sign of hay staching nor digging in her corner. I awoke on the morning that the other does were due and found 10 good sized kits but there wasn't a nest box so she had them on the wire and only 2 made it. I fostered some of Yahtzees big litter over to Panda to even out the numbers. But is was a sad loss, especially when I have lame does like Umi or Indigio that get nest boxes but then dud out and only use them as litter boxes. So if they had the opportunity to breed then count that as a take. And I really need to try and keep attempting to palpate.
Listen and Learn- Pay attention and listen to the cues your rabbits give. If they are not eating then they may not have water or be able to drink. If a good doe abandons her litter look around to see if there is an unseen predator or situation that is causing stress. If a rabbit is sneezing then check for snot, wet paws, etc and quarantine as needed. Most of the time if you catch issues early they can be fixed or at least the rest of your herd can be protected. Your animals cannot speak but they can still tell you stuff.
Three strikes or less- It takes time and money to get a rabbit to breeding age. So if they don't take the first try, have low number of kits, or loose the litter (even when due to neglect) give them at least a second try. The general rule for rabbits is 3 strikes and you cull. For me it depends on the whole picture. Some I only give 2 chances and some I am more forgiving. I have two examples. The first one I had a rabbit that was smaller than I wanted (well technically that is one strike here). She may still have had some filling out to do but was not even 9 lbs yet. She took on her first breeding but then only had 5 kits. She did raise them with no incident but I only could justify keeping her if she had larger litters or her kits were super growers (this being an example, the did not grow incredibly fast). So I culled her. The next example is Indigo. She hasn't had the best breeding takes (she was molting at least one of the times) and she does have around 5 kits per litter. But she is 12 lbs (not fat but big) and I can foster to her anytime. Now that I have been breeding her to bucks that are not silver fox she seems to take better as well. Not sure what that is about...? But she gets to stay.
Be prepared- Last major thing it to be prepared. Keep clean fur from molting rabbit or good pullers for does that don't pull any or enough. Be mentally prepared to cull a kit at any age when needed. It is hard but it is worse to let them suffer or compromise other rabbits. And the rule of kits not being dead until they are warm and dead is very true. Always try to warm a cold or frozen kit, unless it is smashed or squashy looking.
All in all the best lesson is that mistake will happen and the outcome is sometimes excellent and sometimes sad. But try to plan ahead and then move forward with your past mistakes as lessons.