I took a look at those portfolios people have coming out of the Animation Portfolio Workshop and man, I am intimidated yet I took the time trying to study how they construct stuff and it seems a lot more complicated compared to our proccess.
Looking through their process it looks like a lot of construction lines are drawn out to suggest the anatomical structure as well as what they see. I guess more focused studies of anatomical construction wouldn't hurt?
I've also been given a lot of advice to practice drawing 3d shapes at every angle but I am not exactly sure how to approach it. Whenever I do it I am not sure if I am doing it right or how to approach construction of those 3d shapes whether or not to use perspective lines or not, or to just imagine the vanishing points and horizon level and try to draw it with good perspective. The only issue I am finding is actually giving the 3d shapes good perspective. I feel that it might be very essential to progress through with constructions of complicated objects as it the foundation is always important.