Routine and consistency. Everyone in your family needs to follow the same rules.
Basics such as ensuring he sits before he’s fed. That he sits before being let out the door - either to toilet in the garden or to go for a walk. They need to learn that barging out the way is bad manners.
I found the general idea of “four paws on the floor” a good one. Discourage jumping up and barging - not a good look with a giant breed dog.
As soon as you can, after getting them used to verbal instructions, start introducing hand signals for the very basics at least - sit, down, stay, come, go on then (ie you can have your dinner/treat now etc). I had a couple of sessions with a behaviourist and this was a godsend. Dogs really respond to tone and, if you’re having a bad day, your tone can change with instructions. Hand signals, for basic requests, never change - they are consistent (as long as everyone adopts the same signals). Really handy when out and about, bump into people you know and can just give a simple signal to your dog to sit etc.
The main thing, again, is repetition and consistency. Plus ensuring that everyone in the house is on board with what is needed. Dogs need to feel secure in a routine, it takes the pressure off of them. That being said, don’t succumb to any of the “be the alpha” rubbish you might find online.
Also consider puzzle toys designed for dogs - brain stimulation is just as important as walks for them.
And get to know your breed - they’ll all have different motivations and needs, you need to tap into what breed traits are to get the most out of them.