Patrick Siemer's rotoscoping workflow
Patrick's answer does not only contain great rotoscoping tips, but also shows how changing technologies make you constantly adapt your workflow.
I hope this helps....
There was not a single workflow for those spots as they were all different, some had more detail than others, some had different subjects, etc. Each artist had their own technique, which usually depended on the particular footage. Essentially it was all rotoscoped by hand in After Effects, I used Tracker2Mask, and found it better than any other technique.
Start with nicely shot footage. Find one good frame in the shot to do a detailed trace over in adobe Illustrator. This takes artistry and style. but nothing worth doing is easy. You will end up with hundreds of vectors for the one Main "key" frame. We used one key frame for each shot, mostly.
Copy all those vectors and paste them in to AE as masks on a solid, for larger fields of color, just use the "fill" effect to fill with your desired color. For the tapered lines, use Trapcode 3D Stroke, because it it the only stroke effect at that time that had nice tapered ends. After applying hundreds of instances of of fill and stroke in your desired colors, and putting them into position, you can proceed in the best way you see fit. Some people just plowed through and did the whole thing by hand, in AE, setting keyframes for every mask. Some people used Motor, the old Imagineer software that is now call mocha AE... I used Tracker2Mask, It allowed me to stay in AE for all the work, and I found it worked better.
For that to work, you must motion track every possible part of your subjects face and head that you can possibly get a good track on. That may take some time to do, as dozens of raw tracks are needed. There are some other scripts I found useful too, like Average Trackers to generate more accurate tracks, and TrackerViz, for managing raw tracks and stuff, average multiple tracks into rock steady tracks, and use Tracker2Mask to assign the masks to the trackers.
That was a few years ago.... If I needed to do it now, i might try the new ae 3d tracker to get the raw tracks done quicker. I would still use Tracker2Mask to make the masks follow the tracks. Yes it is tedious. Rotosccping will always be tedious, even with awesome scripts like Tracker2Mask. But as I said earlier, nothing worth doing is easy!
PS. Here is a video explanation of some of the techniques, though not tracker2mask, it is quite informative.....