the technical term for the space between key frames - the actual animation - is interpolation. you can edit this in After Effects to make the transition between each frame change, i.e. slow at the start, quicker at the end, etc.
this was the tutorial that i used for it;
The way that key frames could be 'eased' in or out was extremely useful, and i experimented with this using a graph editor. this gives lots more control over the transition, much like drawing a detailed mask in photoshop or illustrator where you would use linear curves to retain the form and shape of the object.
Here are some sceen grabs of the workflow, and a clip of the 'peggy 3d' section to demonstrate my understanding.

