One of the scariest and most enjoyable challenges I've had in my career was designing animation sequences for ABG, Inc. I was part of a group creating distance learning programs for sales people for the agricultural industry. With clients like Eli Lilly and Phizer, our programs taught rather complicated and sophisticated chemistry and biological processes to a sales force that, for the most part, only had a High School education.
Usually how this would work is we would have a meeting with one or two content experts from our client, one of our content experts and myself in a small meeting room. The content experts would then describe a process to me for about twenty minutes. For example, they would talk about the fate in soil for Gromoxone Extra. That is, what does the herbicide do if it was sprayed in a field and parts of the sprayed chemicals do when it missed the plants, and entered the soil? Eventually, they would ask the question: "So, how would you animate this?"
I would usually repeat the process that I just learned about, and made sure I had the main points down. I would then begin drawing up a storyboard on the spot, showing how this process could be described visually. Once the basic storyboard was finished and approved, one of our experts would write the script, and I went back to my office to begin creating or re-purposing 3D objects that I had created before to set up the basic shots. At the time I was using Lightwave 3D.
Once I got the script from our content expert, I would either record the voice-over or have it done. I would animate the necessary sequences, and edit everything together using Premiere Pro.
The animation style was deliberately simple and gives a sense that this material is simple and approachable. I've included some still images throughout this description, but have also have a finished product to show as an example below.