Put all pet supplies out in one area in plain sight. Leashes, bowls, treats, foods, medications, litter, cleaning supplies- broom, dustpan, vacuum, paper towels, carpet cleaner, plastic bags, watering cans, extra bedding, towels to wipe wet paws, etc.
Clearly label medication instructions and schedule.
Leave a well worn T-shirt with your comforting scent.
Schedule interview at medication time if possible, so that the sitter can witness your routine.
In multi-pet households, photos of each pet labeled with names placed in a file folder with medical records.
Tell the truth- don't hedge about aggression or biting history. Forewarned is forearmed.
Update emergency information and any changes in pet routine.
Make sure all animals' collars have current tags.
Have all emergency numbers (the way to reach you or a trusted friend in case of emergency, and your vet's number) written on a single sheet of paper in plain view.
Call your pet sitter as soon as you get back home. This way your sitter knows that you are safe and your pets are being taken care of by you.
Be sure your instructions are clear and comprehensive.