One thing that is usually mentioned only as an after thought is do not pull the trigger while the upper receiver is separated from the lower. The hammer impacting the thin web behind the magazine well may crack it. It can not be repaired.

The amount of cleaning and lubrication has always been a point of contention. You will learn what works well for you. I find that heavy lube when an AR is new helps the rifle "break in" without the usual malfunctions caused by running it dry.

I'm a big believer in dry firing any firearms that can be safely dry fired without damage. Not only will it help your accuracy at the range but you will get needed experience handling your rifle. First remove any ammunition from the room and check that the gun is empty. Pull the charging handle to the rear and release. Check again to make certain there is no ammunition in the room. Pick a small spot on the wall and pull the trigger while concentrating on keeping your sights aligned. Repeat. Dry firing will also point out most problems that may occur with a new gun.

Did I mention that no ammunition should be in the same room as the gun when dry firing and that you need to check that the chamber is empty?