Please return the car clean on the in and outside, this way you will not be charged with unpleasant additional cleaning costs. Don't worry about normal wear and tear, read this article to read about normal vs abnormal wear and tear.
Please make sure to bring the following
All keys
Instruction and maintenance booklet
MOT (APK) form
License plate card
Tire change kit incl. tire (if available)
Locknuts
Carpets front and back
Tow hook, removable parts and cables(if available)
Charge cable and card
Roof rack (if available)