Act in accordance to how you want to be perceived. It sounds simple, but that’s because it is. For example, if you want to be taken seriously, you have to be serious. If you want to be given responsibility, be responsible. If you want to be viewed as trustworthy, do trustworthy things.
If you don’t know where to get started, here are some simple rules that I feel will benefit everyone:
Don’t talk about people when they are not able to defend themselves.
Look optimistically toward the future.
Always try to perform your best/make the most of what abilities you have.
Work hard.
Be respectful.
Do things because you believe that’s the right thing to do, not because someone wants you to.