You are a product of your environment, and by environment I mean the people you interact with. When you are young, you look to others for an example of how you should live your life. If you are lucky, you are surrounded by people of good character, and you learn and develop a similar set of behaviors and ethics.
We all learn from those who have 'been there' and so it gets passed on from one generation to the next. Perhaps you will be able to adapt, and add something which is distinctly yours.
This learning is pretty much free, but you get to pay back later on down the line. In time you will be older and wiser, and others will observe and learn from you. It doesn't take long either. You could be an older brother, and your younger sibling will observe you and learn from you. Often this will happen without your consent or even your awareness.
And what gives weight to your actions that people would take you as a role model? Well, if you appear to be successful that is often enough. The more you achieve, the more people look to you as a template for success. If you achieve via hard work, creativity, or by cheating, it makes no matter. People will see your success and follow in your footsteps.
If you have done some things right and have some measure of success, your credibility will grow. Your power of influence will grow too. And like in the Spiderman movies, "With great power comes great responsibility." You will influence many people, more than you are aware of. If you take the left path or the right path, the high road or the low road, many people will follow you. Your actions will be multiplied by the people you influence. If you do well, you will have company, and if you mess up, you may have more than your own actions on your conscience.
The things others pick up on will not be what you expect either. Don't get stressed out about what they focus on, you can't control it anyways. Just try to live your life the best you can.
Try to live the life of the ultimate role model. Imagine all of your actions are public. Imagine that many people will want to copy you, or at least they will be inspired by your actions. Don't do things that you would not want published in the newspaper.
(Please share your own thoughts and experiences below)