I can't take much credit, honestly, for a lot of his character traits. He never chewed up inappropriate things, he never messed in his crate, he walks well on a leash, he rides well in the car, etc., etc.
I will say that he is fantastic for being groomed. Absolutely fantastic. He still hates his nails being done, but he lets me do them by myself whereas I think if I hadn't worked with him so much he'd probably be one of those dogs you'd have to muzzle/hold down to do. He hops in the tub for baths, holds perfectly still the entire time, lets me clean his ears out/brush him, lets me blow dry him, brush his teeth, etc., etc. All I have to do is put the slip lead on him and hold it like a handler does at a dog show (taunt, up behind the ears) and he immediately holds still and just lets me do what I need to get done.
He's also used to being contained in a room as well as in a crate, which is really nice that he was able to make that association. I worked really hard on his crate training (for him to be quiet and settled in a crate no matter what was going on) and when we were transitioning him from his crate to just being left loose all of the time, we just confined him to a small room while we were away. As a result, while we were staying with a friend and didn't' have his crate, we were able to "crate" him by shutting him up in the guest bedroom's walk in closet and he just settled and went right to sleep because being confined in a room next to ours is "normal" for him.