As a publisher and editor, I can literally tell on the first page of a manuscript whether the book is going to end on the acceptance or rejection pile. I'm sure all you authors out there are eager to hear what to avoid if you want to get through the gatekeeping process.
Tell it all on page 1. How could you possibly do that on a single page, well, you would be surprised. Some authors give the book's big reveal on the very first page. They think this technique effectively draws in the reader -- and it could if you're a master of the storytelling process. Truth is, most new authors are not masters of that process, and the big reveal only serves to ruin the book's chances of getting accepted. So unless you're super talented and can pull that one off in some clever, interesting way, I don't recommend you approach your book's story that way.
Passive voice and cluttered writing. Two-hundred adjectives strung together with a lot of passive voice is a big no, no. Believe it or not, use your adjectives sparingly and you'll look much more brilliant than if you take a handful and spray them on the page. First, all those "desperate" adjectives are sure signs of a beginner. Seasoned writers always know better. If you have no idea what is passive voice then I can't help you with that one. You need to look it up and understand to avoid it. Passive voice sinks your writing and bogs it down like concrete slippers.
Run-on sentences. Too often, especially with academic writers, the belief that a long sentence makes you look brilliant. Do you know what happens when you write run-on sentences? The reader has to go back to your noun-subject agreement and figure out what the heck you are talking about. It's exhausting! Readers continually have to read and re-read just to understand what you just wrote. Mix up longer and shorter sentences to keep your writing popping along. Do not write run-on sentences, especially in fiction. You will lose your readers' interest in minutes.