I find the best part of re-prepping is to go deeper into the places that I couldn't before. So I got my main character but not the side characters? I might use them as the protag and antag inspirations and profile who I haven't spent a lot of time with. I'll change something because there's a reason the novel fizzled instead of sizzled last year. What does it need? Where do you need to go?

My world building is also what I focus on during a re-envisioning of what I wanted but couldn't quite manage. Those plot holes, too, is where I bring more time. I knew these events, but I didn't get the complications or the nuances of character that bring more into it.

Sometimes it is easier just to take each thing and redo it, then compare with the previous year. Either way, I'm sure you'll find a stronger story once you redo your prep. Hang in there!! It's never easy.