Humiliation photos:

Start a photo library (great for privacy, these digital cameras). Start with simple stuff - parade her in her costumes / appliances. Then work up to captions, like holding a placard or banner with "I am a fuck slut" up while in costume.

Once you have worked into a routine, photograph your progress. Keep an album of prints with a title on the spine. Get a remote control so you can take photos of yourself dominating her in your chosen manner (or maybe penetrating her, etc.)

Just an idea!