You may have noticed that I am sometimes pretty hard on people who have published famous books and who have made far more money than I have doing it. Am I just some jerk who thinks he didn’t get what he deserved? No. I am often a fan of the works I pick apart. That is just it though. You have to go into reading thinking like an editor. Figure out every possible flaw and every positive quirk. Pick the work of the greats apart like plucking the petals from a rose. It looks like you’ve destroyed the beauty of the thing afterward, but you will fully understand where the best parts of the work were and why they worked as well as they did.
You will also recognize where they made mistakes. Recognizing a mistake means you are less likely to commit that mistake yourself. The great writers of every era have put forth new ideas that then get copied endlessly. Eventually, a few who imitated the things they did right will also overcome their mistakes and strike a nerve on what will refine that story into a near-perfect narrative. If you had never read the book Frankenstein, you would probably never know how far it deviates from the modern telling. Newer works touched on aspects of the story that worked and added elements that were missing from the original Neither is better or worse, but the one that stuck with us had more elements that struck a nerve with the reader.
Even looking further back, the version of Romeo and Juliet we know was the fourth to exist. In those days, you could steal the story of another as long as you did it better and Shakespeare did it far better than any before and in my opinion, since. He took what worked and removed or improved what didn’t. I am not saying to steal the works of the greats, but I am saying that you can learn both their skills and their failings. You have to first be willing to see those failings instead of overlooking them however. So find your favorite novel and go in for surgery. Dissect the novel like a surgeon and find every good thing you can so that you can understand why it is so good. Pull out ever ruined moment and terrible phrase and study what makes them such a poor choice. Put it all back together again in your mind and when you go to write, remember that template for improvement.