I loved Cesar Millan's programmes. I think plenty of exercise and activity is essential, or dogs get bored, lonely and frustrated, then they misbehave.
A dog shouldn't be left alone while its owners are out at work all day.
Pitbulls are banned here in UK, but that's because stupid and cruel people had used them for fighting contests and they became savage and dangerous.

With any training, firmness, repetition, consistency and rewards are probably necessary.

I find that works with husbands too, hee hee :)