I was fortunate enough to storyboard and animate a spot for Walmart Canada featuring their Great Value brand frozen pizza. This spot was especially fun due to my background in kids cartoons.
With a scratch track, and voice work done by my talented producer at the time; we laid the groundwork by creating a pre-vis and a set of boards. The pre-vis was made using Maya and early geometry, and the boards were done in Photoshop.
Once the models were prepped and rigged, I was able to move ahead with animation. I usually start with stepped keys and move onto breakdowns. This process is similar to traditional paper and pencil animation, which is how I was originally trained.