Some novels are meant to transport a reader into a new world while others strive to portray the everyday, normal teenage existence. Been a little too long since you've been there? Me, too. Before you send your character off on a midnight drive, you might want to consider if they're even licensed to be behind the wheel after eleven o'clock at night.
This nifty website has a drop down menu to select any state in the US to see restrictions for drivers under eighteen.
Wondering what textbook your character will pretend to read while secretly making eyes at someone a few rows over? While curriculum varies, this wikipedia article breaks down education in the states and what's required by section (middle school, junior high, high school).
Does your character work after school? The U.S. Department of Labor site will outline requirements for work permits, how many hours a minor may work and how late.
Think the legal drinking age is 21 in all states? Not necessarily. There are exceptions to this rule including religious, medical, private clubs, or even the presence of a consenting adult. This website breaks it down and also includes the legal drinking ages around the world.
Family dynamics play a role in almost all novels. The single parent home is a common denominator in many YA novels, and with good reason. This site lists the percentage of single family homes by state. The chart on the side also links to some other great demographics for teen population, ethnicity, pregnancy, poverty, and high school dropout rates.
Not all novels are meant to mimic real life. The emotions and choices your characters make are ultimately what readers connect to. That being said, just because our stories are fictional doesn't mean it hurts to do some fact checking. If you're looking for things that teens will identify with in their day to day routines, these links can provide some great information.