* Make the scene easy for the animator to understand and use.
That means COMPOSING THE SCENE so that there is enough space for the animator to move the characters - and to clearly see what the characters are doing.
*Preserve the GUTS of the storyboard poses - AND HOPEFULLY TO PUSH THEM FURTHER.
Here is more detail on how to plan a scene for layout:
John K Stuff: Scene Planning For TV - Setups for storyboard and layout 5: Roughing The Widest Staging
***Ideally, a layout artist should be an animator with a sense of design and composition. The most skillful artists that combine great draftsmanship with a personal style are the artists best suited to layout.
That's a hard combination to find these days.