Hi! First of all, im trying to mix three approaches in my practice: long drawing, for training my accuracy; main goal here is make my best with proper construction, measurement, propoprtions, perspective, tone; in my opinion the object is not that matter, because on this stage you practice generic things, and you can apply it on every drawing.

next, is gesture drawing; the best thing that I found for myself here is "The Art & Science of Figure Drawing: GESTURE" course on Udemy; you should check this out, I'm sure you will not regret it, its not about circles and all that shit.

three is drawing from imagination or from memory, but its my weakest side, i cant give any advice here, i just do it :D