Respect shown is respect earned. If every person on Earth respected each other, disagreements resulting in dangerous behavior, I believe, would be far more scarce.
Too often we try to use pure logic to debate. We tend to forget that how an argument is presented can often be just as important as the argument itself to captivate and endear our audience.
This goes for everything. Buying a new car? Get in an accident? Someone say something offensive? A few minutes of thinking and waiting before saying or doing anything significant can change the outcome of your day, week, month or even life.
Learning how to do this is difficult, especially when you're young. But learning to let go of anger when it serves no purpose is empowering, and you'll spend a lot less time seething over something you can't or shouldn't change.
There's a time and place for debate, and knee-jerk reactions from extremely biased people on either side serve very little purpose besides sucking away your free time. Find a proper forum for discussion and have a real debate.
Many people would have us feel guilt at all things positive in our lives in an attempt to bring attention to people less well off. Help who you can to the best of your ability, but don't succumb to purposeless guilt.
You should doubt that someone's magic tonic will cure you of all that ails you, but living with the belief that everyone is horrible or is out to get you is worse than being gullible.
Lying shouldn't be for personal gain, but "never lie" isn't quite right either. If you can tell a small lie to lessen the load of stress on a loved one ("You go on, I already did the laundry!" Then frantically doing the laundry before they get home.) then don't feel bad.
You should always be as good as you can be. It won't be the same every day, and some days it won't be very good at all, but always try. Those who notice will appreciate it more than you can imagine.