I've spent several hours researching how to plan for this as well as continuing to work on the script. I'm no expert but here's my plan so far.

Pre-Production
1. Script
2. Concept sketches
3. Create two lists based on the script and the concept sketches.
a. List of EVERY object that will exist in the production
b. List of EVERY event that will exist in the production.
4. Storyboard
5. Very low rez blocking of animation, nothing fancy. This will help for figuring out timing, camera movements, etc.

Production
6. List of requirements like Maya, Photoshop, plug-ins, ncloth, etc. Basically do we have everything we need to put the production together.
7. Assign tasks like objects to be modeled or events to be created/developed
8. Texturing
9. Lighting
10. Animation
11. Put it all together
12. Rendering

Post-Production
13. Editing
14. Compositing

This list may change as I do more research but this is what I have so far. Any thoughts, ideas, etc are welcome. I have no experience in this so I'm all ears.