I feel as if everyone around you has an impact on you and your morals whether it is changing your mind or making you think .5 or 50 percent. Your parents have had a great deal of influence in your life, starting this cycle of what you know/think is the right thing to do compared to the wrong and everything else that follows. You learn these things by the way your parents punish you, if they punish you at all, and this is when children start learning the "right and wrong" things.
Teachers and coaches are another factor with moral development because they are your parents away from home. They are the ones that teach you everything else your parents do not teach you. You learn the proper way to interact with classmates and teammates along with the wrong and inappropriate ways to do so.
There are plenty of other people in your life that can be used as examples of how you use them in parts of your moral development but knowing so, should want to motivate you to try to be the best person as a way of motivating others to be their best person.