What Are Your Housesitting Best Practices?

Some are very similar to yours. Here are mine:

1. Prepare well. I send out a pre-stay survey where I not only get all the contact info I need (their's, a local emergency contact, a vet, etc), but also collect info on behavioral challenges for their pets, house rules, feeding and medication instructions, etc. Part of this survey is asking them if they'd like me to send multiple updates per day. I've noticed many pet parents would check in with me on Day 1 before I got around to sending an update, and I've found that ALL of them appreciate having an almost immediate update shortly after you arrive. I try to do morning and evening updates - to calm their nerves and also to show them that I don't just do the bare minimum (aka 1 update per day).
2. Leave the house cleaner than I found it. Take out alllll the trash, even if it was there when I arrived. Wash all the sheets, blankets, and bath and kitchen towels I used and put them back where they're supposed to go (inform the owners so they know I cleaned everything and didn't just make the bed with used sheets). Sort all the mail by recipient.
3. Pretend there's video cameras. Don't do anything they wouldn't approve of, even if they wouldn't find out (e.g. using their personal products/razors, breaking house rules, etc).
4. Don't overstay my welcome. Usually this means staying too long, but I'm thinking specifically about food. Often people say "help yourself to ANYthing," but I usually only help myself to things that are going to expire while they're gone (milk, fresh produce, etc) or items they have an excess of.
5. Updates are not "I fed them and went for a walk at 1pm." Updates are personal and informative - "Rex gets so excited when it's breakfast time. He runs around all over the place and doesn't even realize his food is on the ground waiting for him. He is just too adorable!"
6. Leave a welcome home gift bag with little goodies for the owners. Include a hand-written, preferable dog-themed (or cat-themed for cat sitting) thank you card with genuine reflection on how amazing their pets are. I also include a home-made doggie report card, where I fill in moods I noticed (friendly, playful, shy, etc), bowel and eating habits overall, energy level while in my care, and comments. I also have a spot where I circle "Don't forget to leave a review" to help cue them to leave a review.

Mine are essentially the same: Clean house/dishes, take out trash, make bed, straighten things up a bit, ensure doors and windows are locked at all times, water plants, I rarely eat anything of theirs, even if they ask me to (aside from salt or pepper, a bit of sugar for coffee, etc), wash dog bowls, pick up all dog toys. I also text them as soon as I arrive and right before I leave. My goal is to make the house look as if I was never there, and leave the doggies happy and safe!