That video seems okay, but clicking through it I noticed a couple problems. One, don't lubricate your buffer spring. It should be dry, or at most just use the slight residue of oil left on your hands to rub it down before reinserting. Second, don't use a dental pick in your star chamber. Yeah it's easy, but it also has the potential of scratching the barrel extension.

I'm sure there are more issues, to me, in that video, but everyone has their quirks when cleaning ARs. Good luck.