Everyone has a gift, even the person you think is a total bum. Look at what Harry's aunt and uncle ended up discovering about him!
Revenge tends to only make you look bad. Harry may at times have tried to get his icky cousin into trouble, but it always backfired.
People may be following your progress (or your example) even if you don't know it. Harry had no idea that so many people were interested in how he was doing before he headed out to Hogwarts for the first time.
Fame may not be all it's cracked up to be. Harry Potter arrived at Hogwarts with a reputation already in place. While it may have paid off in some ways, it also attracted the envy and negative attention of boys like Malfoy.
People are complicated and it's difficult to see all of their soul in one fell swoop. At first, Hermione seemed like a very uptight show-off. It took a long time for Harry and others to see what a good heart she had.
It's easy to be a rival. It's difficult to be a compassionate rival.
Things are seldom as they appear. Hagrid seemed big and scary and his pets often seemed quite monstrous, but in fact Hagrid was one of the most trustworthy people at the school, and his pets were loving creatures.
Alliances are important. There are a lot of alliances throughout the Harry Potter story. People create alliances for strength or to change the way things are.
Alliances can be dangerous. When you are allies with a group of people, your fates are intertwined. You are sharing your vulnerable spots, and it’s easy for things to go awry. That is not to say you should avoid alliances, but you must choose carefully to avoid harm.
Two friends can be better than a host. In the end, Ron and Hermione were enough to sustain Harry through the hardest parts of his journey.
Sometimes you have to let people help you even if you feel like you can do everything yourself.
You never know a person's full story or rationale for doing things. We can't reside in peoples' heads. Even Snape had problems with that.
Don't ask others to do what you wouldn’t do yourself. The story would have been quite different if Harry had said," Yeah…you guys go fight the dark lord. I’m just uh…I'm just gonna chill here I think."
Look for people who can balance you somehow. Harry's darkness was balanced by Ron's impish sense of humor. His passion was balanced by Hermione's logic.
The people who are there for you in the dark times and who are there to celebrate with you when you succeed – those are the people you want and need in your corner.