Revision is the art of taking critical feedback and turning it into better writing. I didn't feel comfortable with revisions until at least...gosh, maybe five manuscripts into my writing journey, and it really held me back from growing creatively. I hope some of my observations are helpful to you.
I run a critique partner matchmaking service. As such, I get exposed to hundreds of writers. One thing the successful ones have in common: they can accept critical feedback and make related revisions.
I want to give a list of revisions issues I see writers face that have held them back from meeting their potential. Spoiler alert--I've done almost all of these myself in varying degrees of awfulness.
Unwillingness to outline, brainstorm, or use prewriting tools
Unwillingness to learn industry standard word counts and as a result create work that is much too long or short
Argumentativeness with critique partners and beta readers, bullying their readers into changing their opinions
Inability to delve into the deeper, structural issues reflected in reader feedback, making only surface-level changes
Lack of research and professional learning, which leads to less skill in interpreting critical feedback
Crippling self-doubt and self-recrimination when confronted with criticism
Inability to learn lessons while writing one book and apply those lessons to the next book
Inability to self-examine and change their creative process as needed
Unwillingness to recognize other people as experts and insistence on retaining that title at all times, thus discrediting reader feedback
Here's the problem, once you've overcome all those obstacles: If four people read your book, you'll get four different sets of prescriptive notes. The question becomes: How do you know which notes to take and which to discard? Well, I can offer you this: I lived in Texas for four years, and I heard a man say the following: "If two people call you a jackass, it's time to get a saddle." If two different qualified people say the same thing about your manuscript, it's time to address that issue.
If you have an anchor such as a beat sheet or another outlining tool, you can use that against the notes you're getting to get at the heart of what's bothering the reader. For example, your reader might complain that the main character is boring in the first five chapters. But if you look at your beat sheet, you might realize that you failed to hit certain key beats that drive the story forward. So the issue IS that the reader is getting bored, but the real fix is plot here, not character.
Revision is the art of listening. It's questioning, digging deeper into someone's thoughts, squelching pride and agony as you realize how much work you'll have to undo. It's the art of investigation, into your reader's thoughts and into your own process. Are you focusing too much on plot and not enough on character development so that every reader complains about not "connecting" to your main character? This is a hard truth, and it's one I've had to face.
Now go write stuff, and delete stuff, and buy your critique partners a drink. They deserve it! Anyone willing to brave a writer's stubbornness is worthy of sainthood.