First, you do your best to select a breeder who you think cares about the breed. You pick a breeder who health tests, who lets you see the puppies, who lets you see the sire and dam, and who provides you with a pedigree.
Next, when you bring that puppy home, keep her in your house, welcome her on your furniture, and give her toys to stimulate her little mind.
Give her some rules. If you play tug (and please do play tug), make sure "drop it" is in your puppy's vocabulary. If you must, teach it in German (aus) to sound extra tough.
Really vary the toys, so that neither of you get bored with the prospect of spending another moment with the same piece of battered rubber.
Make sure to get out in the world and get plenty of exercise!
Be sure to read training books, because your dog is your responsibility. That's financially, and legally. Your dog's actions are your liability.
Also remember, the dog you raise is the dog you live with. Your dogs wants to trust you, wants to know you'll make good decisions, and wants you to have her back.
Don't disappoint her. Drop this "mean" stuff and just try to raise a good, balanced dog. If you train and socialize your Doberman, she'll know rise to the occasion if necessary. But don't set out to put your dog in bad situations. You won't like the result.