The tricky part is someone has to be boss, otherwise there is anarchy.
My dogs knew I was boss. With the first I just expected her to do what I said and rewarded her with praise and attention when she did it. She had not been abused physically but had been very lonely as her former owner was afraid of her. Dumb ol me didn't have enough sense to be afraid and was not inclined to let her run things either so we got along just fine after the first day.