Have you ever read "Travel by Wire!"? It was the first story that Arthur C. Clarke published. It's... youthful in its writing.
Or how about Pebble in the Sky?
> Boucher and McComas were disappointed by the novel, saying that despite Asimov's good ideas, "his heavy treatment and routine plot are disappointing.
Try to find a copy of The Big U by Neal Stephenson. https://en.wikipedia.org/wiki/The_Big_U ("When Stephenson's Snow Crash was published in 1992, the book that became a best-seller and vaulted him to fame, The Big U was out of print and Stephenson was content to leave it that way. When original editions began selling on eBay for hundreds of dollars, he relented and allowed The Big U to be republished, saying that the only thing worse than people reading the book was paying that much to read it.")
Or Sundiver being a much weaker book than the rest of the Uplift series.
Or A Planet Called Treason by Orson Scott Card (which was even worse when I reread it as an adult).
Old Man's War was Scalzi's first "real" story... one that he had in the back of his mind to write in his college years.
He has matured as a writer since then.