As I mentioned earlier, I had a hard time finishing a sketchbook, so the solution was to just sketch on xerox paper and put it in a looseleaf binder. Instant sketchbook! That also made it easier to deep six drawings that truly stunk.With a bound sketchbook you're either stuck with them or you have to figure out how to obscure or enhance them in some fashion. Granted this approach doesn't produce an object with the talismanic energy a real sketchbook has, but it seemed as close as I could get at the time.
About 15 years ago, I went through another intensive drawing period where I was convinced that the obsessive drawing of objects would permanently imbed them in my brain. It turns out to not really work like that (you still have to deliberately create a codified representation of the object for yourself), but it did improve my capacity for accurate drawing from life.
Included here is a group of obsessive shoe studies, and likewise of a nice resin cast skull my wife got me for my birthday from the bone specimen shop -Maxilla and Mandible in Manhattan.