If you really want to be an artist one thing you have to be able to get is good feedback from people, past a certain point you can’t progress any other way.
First of course you need to be able to take criticism objectively, it can hurt but that it’s only way you can improve.
The harder part is being able to get useful feedback, most people are not that good about giving you information you can use. They want to spare your feelings by talking about what they like and what works well or they are not able to easily articulate what was wrong.
Learning that part of your novel works well is not helpful, you already thought that (or you should not have put it in). This means you need to nail people down on not only what does not work but why. This can get frustrating but if you only know that a certain part of your book is boring, but not why, you can’t fix it.
You also need to know that not everyone will be right, this is why you need to really understand why people feel a certain way about the book. Sometimes you will have to ignore criticism, this is why you should have several readers from several different backgrounds.