There are folks on this board who are true experts with dogs. I just have one.
I adopted a large, lab-mix dog (she's my profile pic

). Like many new owners I took her to obedience class, they gave up on her, took her to another class, same thing, found a dog walker/trainer .... same thing.
So we set out mostly on our own.
We made sure it's been fun on both ends of the leash. I work constantly on her behaviors. Yes, she still has "issues" but she's a different dog than I adopted and we've both learned a lot.