Sketching hard-surface objects is much simpler than you might have imagined. You'll learn solid perspective skills to set up your scene, and the discipline to stick to these guidelines. Aaron will demo a complex environment using the same foundations covered in the lesson.
Beginner: Sketch 1-5 hard-surfaced environments using photo reference of observation from life. Try and vary the compositions, and focus on a variety of subjects such as architecture, machinery, vehicles, etc. Make all the sketches different to keep it interesting for you.
Advanced: Design a minimum of 3 or more invented architectural or mechanical environments, using photo reference or real life observation as a guide. To keep things simple, you can decide how much of the environment is invented or from reference, but at the very least design something unique for the focal point.
In addition to your sketches, do a page of studies that shows objects from your composition in more detail, such as bridge supports, lighting fixtures, ducting units, decorative architecture, or any elements you find interesting that tell us more about your architectural space.