I broached this with a friend whose children were all older than mine so she knew the ropes.
She said, "I am Snow White, I have Smelly, Clumsy, Dozy, Greedy and Sweet-But-Forgetful".
I think the message was her DCs had their foibles but there was usually one overwhelming factor that bugged her. So she picked her battles. And like a toddler, with each one she lavished praise when they were polite, organised, punctual. She took herself off to bed early with the kind of routine we lavish on babies and small DCs - a bath, a cosy bed and a book - with scented candles and her choice of music or tv in the bedroom.
That and she got her DH to remove a bedroom door if things got to the point where they stamped upstairs and slammed a door.
Sometimes there's other factors but our flesh and blood can wind us up like no others.
Always be explicit, never ambiguous with instructions.
If possible, allow some face-saving wiggle room, if they at least try. Not so that he can talk you round, but so that if it feels appropriate you can give an inch.
If you confiscate something, give him the chance to earn it back.
If ever he appears ungrateful or careless, ask yourself, am I doing this for him, or because it makes me feel like Super Mum? eg clearing room of stuff, ("Don't touch my things!"), making a really nice meal he then barely touches because he's stuffed his face with sweets.
Make time for yourself, try and get outdoors, can you take up a hobby like swimming or yoga or choir that you can escape for an hour or two?
If you worry about the teen years maybe you could look into parenting courses locally.