Zoom in on the first chapter. If the editor is not engaged immediately, you've lost the battle. Read your first three paragraphs. Be honest with yourself. Break it down sentence by sentence.
Many writers try to pack as much background information into the first chapter as possible.
Instead, jump into the middle of the action. Weave the background information in as the story unfolds. We don't need to know everything right up front. I call it this, because I once read a novel where the author took an entire four pages to describe the protagonist's English garden. It wasn't crucial to the plot or the character's development.