My hook paragraphs always have the same four component:
Motivation - Who is the protagonist and what is their goal? Introduce the protag and what their story is. I do this one of three ways: either by giving the era and location (ex: Set in modern day New Hampshire -or- During the long, hot, summer of '65), setting up my main character (ex: Logan Daniels has always led a sheltered, predictable life in sleepy Lancaster, New Hampshire -or- High school as never been effortless for Juice Zander, and her sophomore year is no exception), or using a variation on the "when" formula, (ex: Following the death of his wife -or- While interviewing a drug-addicted celebrity)
Conflict - What is keeping the protagonist from achieving their goal? Introduce the big problem in your protag's life. Make certain to keep the focus on the protag and only identify key secondary players by the way they relate to the protag (ex: the teen's mother -or- a reluctant ex-husband, etc.)
Plot - How will the protagonist overcome this problem? The conflict should segue nicely to the actual plot. What's going to happen to your protag? Don't exercise your vocabulary chops here; be tight, concise, and just lay out the highlighted plot points.
Stakes - What happens if the protagonist fails and what choice(s) does the protagonist have the make to succeed? Here is where you have to make the agent or the reader care. If you don't do your job right, no one will care what happens to your protag. But, by all means, leave the reader hanging, ever so slightly. You absolutely want them to die if they don't find out what happens to your character.
Next up: Writing Your Bio...even if you've never been published!