I have recently sent my novel to my editor. This is the month when I take a breather and step away from it as it begins to get reviewed by others.
My editor does more than Copy-Edits. She covers the whole spectrum. Find a good editor and PAY them. They are the best investment.
I will get a pile of feedback about what works, what doesn't, where it's weak and just plain F'd up.
At first taking suggestions from others was difficult for me. This book was my baby! What do you mean, my baby is ugly!?
The key here is to find the right people to help you make your book not suck. Finding the right editor is tough enough. Finding Beta-readers is even more difficult.
A Beta-reader is someone that reads my book when it is in the final stages and gives me feedback on everything. They comment on characters, plot, settings and anything else. You don't need to take all your recommendations but if ten people ALL tell you that chapter ruined their lives forever, they may be onto something. This feedback always makes my books better.
The willingness to change is kind of a superpower. It will result in better reviews and more sales.
I met an aspiring author that had been working on the same novel for 30 years. At the first suggestions in our writers-group (the reason for the group) he flew off the handle. Stormed off in a fury and we were being nice to him because he was a first timer. He came for praise, not help.