Warning : This post contains spoilers.
1. Your family isn't exclusively your blood relatives
The definition of family is pretty straight forward: all the descendants of a common ancestor. However, just because Harry doesn't have red hair, it doesn't mean that he's any less a Weasley. We see very early on in the series how Ron, Fred, and George risk so much for hair by rescuing him from the Dursley's in Harry Potter and the Chamber of Secrets. We see Christmas dinners and Christmas presents and loving hugs from Molly. We see Harry welcomed with open arms from the very first movie we see the Weasley household. 
2. Rely on your friends.
Without a doubt, the Golden Trio is one of the most memorable friend groups in our era. Each one supported each other through the tasks and turmoil of their lives, and each one has a unique trait – almost like a super power – that helps complete the other two. Hermoine, of course, is the brains. Ron brings selflessness and courage. Harry brings leadership and power.
Most strong friendships operate that way. We look for qualities in other people that are missing from our own lives in order to complete ourselves.
3. A life without love is not a life worth living.
In Harry Potter and the Order of the Phoenix, Harry fights off Voldemort by remembering what it feels like to love and be loved by others. "You're the weak one," he says, "And you'll never know love or friendship. And I feel sorry for you." Throughout the series, we are constantly reminded of the power of love, starting with the first book in which Lily's love destroys Quirrell. Without love or passion, life is empty. 
4. Laughter is the best medicine.
The twins love their pranks and their jokes, and they make a successful business out of it. In Harry Potter and the Half-Blood Prince, there's the stark difference in Diagon Alley where most of the alley has shut down, but Weasley & Weasley is going strong. They're the light at the end of the dark alleyway. And laughter is the light in the dark. Remember that, when things get tough, a little lift to the spirits might do you some good.
5. Real strength comes from within.
Neville Longbottom is, without a doubt, one of the most courageous and heroic characters that J.K. Rowling created. He stands by his friends. He stands up to his friends. Neville, on the outside, particularly in the earlier movies, does not seem strong. He's a dorky, awkward student who dreads his plAsacement in Gryffindor – surely he would have been better placed in Hufflepuff. But the Sorting Hat saw the strength inside Neville from the very beginning.
6. Once you've hit rock bottom, the only place left to go is up.
This is more of a J.K. Rowling lesson – Jo has said that when she first had the idea for Harry Potter, she was not in a very prosperous place in her life. She's quoted as describing "rock bottom" as "solid foundation that [she] rebuilt [her] life." It's a philosophy that helps me get through those types of days.
7. Heroes aren't always good people.
There was a lot of controversy when Harry names his son Albus Severus Potter after the best/bravest men... We've been watching Harry Potter this weekend in my sorority's lounge, almost impulsively, and my friend said aloud, "Dumbledore's a dick." Throughout his life, he manipulates Harry and uses him as a pawn in the fight against Dumbledore. Snape, although I will defend him with my life, abuses Harry – bullying him like James did to Severus. He is drawn to the dark arts and to Voldemort and only realizes his mistake when it directly affects him. 
However, both Dumbledore's and Snape's sacrifices are heroic and were crucial in the fight against Voldemort. It's important to learn the seperation between heroic and good.
8. Breaking the rules is worth the adventure.
As someone whose life philosophy is "Do it for the story," adventure is the most important thing in life. The memories that you create are the only things that you really "have." Rules are constructs, subjective. A lot can be bent and broken without any real consequences. Don't go around killing people, but "Do not trespass" is more guidelines than anything else. 
