As above listen for rattling first start of the day. If it starts doing it stop using the car as soon as possible.
If it doesn't have oil blockers fitted to the cam magnets then fit them - not expensive and easy to do yourself.
If it's an auto do regular gearbox oil and filter changes. MB touted these gearboxes as being sealed for life but to them life meant until it broke! Every 40k miles should keep it all running sweet.
Serpentine belt pulleys and tensioners can rattle after a while - easy fix and cheap to do.
Other than that just drive it and enjoy it.