Welcome to dog showing Nightgrace6.
Firstly, don't over train your puppy. You want her to enjoy it at all times or you will end up with a bored dog. Babies are allowed to be less than perfectly behaved in the ring.
To practice stacking her, look at photos of other dobermans and try to emulate how they are stood. A mirror or reflection in a window is a handy tool. Also you can practice baiting her into free standing by using food or a toy. Try to get her to 'walk in' so she is standing 4 square, and very attentive.
At the end of each session give lots and lots of praise. Whether at a show, running around a park, or training on the road....my dogs always came home believing they'd won Best In Show.
Good luck with your baby.