From my sketchbook practice with dominant straight lines. In fact, I force my pen to snap to vertical and horizontal as much as possible. I'm keeping the values simple to a max of 4 shades and, I aim for a time spent per sketch somewhere between 1-4h.
The sketch are done primarily in 3 steps:
Step 1. Layout and proportions
Step 2. Basic depth as max and min shades
Step 3. Adding the details