Seeking advanced critique: torso-pelvis proportions, landmarks, and value.

[Richard.L]

I've been attending a weekly life drawing session for six months to improve my anatomy and gesture, and while I feel more confident capturing the overall pose quickly, my longer studies still have major issues with proportion, especially in the torso and pelvis relationship, and my shading feels flat and doesn't describe the form convincingly. I'm looking for a constructive figure drawing critique that goes beyond general advice, focusing specifically on how to see and correct proportional errors in my own work and how to use value to create volume. For artists who have moved past the beginner stage, what specific landmarks or measuring techniques do you use to check proportions on a standing or seated figure, and how do you approach building up tonal values to make the figure look solid and grounded rather than just a shaded outline?