This paragraph illustrates a hook. It would be at the beginning of a book, or at the beginning or the end of a chapter. It's something used to ensnare a reader, to make them want to read more. At the beginning of a book, it's used to get the reader to buy the book. At the end of the chapter, it's used to make the reader to keep on turning pages, not wanting them to stop at the end of the chapter. When the reader does stop at the end of the chapter, they're not as likely to pick up the book. If they stop in the middle of the chapter, they're more likely to keep on reading, for chapter closure. It's the same for the beginning of a chapter.
So what makes a good hook? Watch any television show or movie. What would play out well in a scene before the first commercial or the opening credits? They don't want to lose their viewers before any break, so they stack the odds in the show to keep you wanting to come back after the break.
A hook has to include something that puts the character in danger, forces them to make a decision that has consequences, or shows something that changed them as a person that happened in the past that is relevant to today (not back story). Or, it can be something simple that is endearing to the reader. Whatever you use, make it compelling--the reader has to want to read more, to invest time and money in your story.
Hooks have evolved over the years. If you pick up a book that was published back in the 90s, you'll see pages and pages of back story at the beginning of a book. But with the advent of more action packed movies and television shows, viewers want to see and read something that is more meaningful or dangerous. They want to know what happens next. What will the character do when faced with the situation they're in?
Also, since pacing is a lot faster these days, the first few paragraphs of the book or chapter, and the ending of the chapters, can't drag. That's not the time to describe a room, for example. It should be the 'before the commercial' break, to make the reader want to keep on reading.
Good luck with your hook. It will make or break your book, once a reader has decided to open the thing. What makes them open the book? 'Curb appeal'--the title and the cover. If either of those aren't good, forget sales and forget about the reader ever seeing page one or your hook.
Have a great week!