More ID sketching practice, followed by perspective and section drawing studies. Slowly trying to internalize as much of the information and technique as possible through repetition. Key points to focus on: line accuracy, line quality, tangency issues and proportion (creating pleasing 3D forms).
And a couple of sketchbook pages. Really loose and scribbly - mostly just messing around and trying to come up with interesting designs as opposed to focusing on cleanliness (or that could be just another excuse for laziness). Also, it's time to get a new sketchbook!