i don't really have a particular approach to it really, in the challenge i basically did what marc asked but i always tried to push it a little further.
If i would to tell what i was thinking when doing these, i always considered how the perspective would affect it, even when i didn't put on the marks on the sheet. Also, it's always good to break down smaller volumes in bigger volumes before hand, take day 17 of the challenge i did for example, i did a big cylinder being squashed by the donut thing, then i break the big one in to smaller ones, always drawing the ones in front first.
In my eyes your animal simplification turn out pretty good, only the cat's tail looks bit odd, that's because the flow of the fur can be quite deceiving, you represent it as an S curve, but i feel a C one would do a better job portraying the volume receding in and then out of the horizon.
marc did a video about volumes recently, there's some awesome exercises that are quite helpful in there
And just so you know, i'm accompanying yours and gordon use of the force method for gesture and i'm actually trying to do something similar with my gestures, i think your style of gesture looks pretty cool
