Read more debut novels!
I used to avoid debut novels, thinking they wouldn't be as good as work by more established authors. It took writing my own novel and learning what it takes to get published to change my thinking.
Debut novels are gold! It takes a lot to break through for the first time, so there's something really special in that first published work. Plus, the author may have spent years polishing the plot, deepening the characters, and perfecting the prose while they worked toward publication. Everyone (agent, editor, publisher) wants perfection with the first published novel.
Now I seek them out, expecting something special in every first novel. Some examples of debut novels I love: Looking for Alaska, Ready Player One, The Martian, The Rosie Project, The Help, The Kite Runner, The Woman in the Window, Wonder, Miss Peregrine's Home for Peculiar Children, The Catcher in the Rye.