There have been three things which I have found to be successful as a dog trainer working with problem dogs in real life situations
1 – Examining and understanding the function of behaviour - what is the dog hoping to achieve by doing that?
2 – Being excellent at our own movement - we are holding the leash and moving with our dogs, knowing how, where, when to move is vital
3 – Paying attention to the detail - it's not the big things which count, it's becoming increasingly better at all the little things and mastering them