Via Joelle Charbonneau via Chuck Wendig, 15 ways an author can know a manuscript is ready for submission.
7. Your first chapter ends on a fabulous, page turning hook. You know those authors that you love to curse out because they kept you up all night reading when you should have been getting sleep. You want to be one of those people. If your characters go to sleep at the end of a chapter, your reader will probably remember that they are supposed to get rest and put the book down. End the first chapter in a great hook and the reader will flip the page with you and suffer at work for it the next day.