A bully is not someone who constantly turns off your computer when you are using it, nor are they a person who purposefully bumps into you when your walking. They are any person that is trying to cause harm in an effort to seem better than you.
Contrary to popular belief:
There are NO signs of a true-blue bully. There is nothing in a person's behavior that will show you that they will grow up to give some poor person issues. There is nothing in a person's past that will show you how they will treat others in the future. There is nothing because everybody's different. There is no way because nobody thinks/reacts in the exact same manner. We, at very young ages, are groomed to believe that we are all individuals, and we are. But still with all that variety there is always another person who thinks like you, who believes in the same miracles, who loved the pleasure of childhood, and who couldn't stand it. And if all this is true, then the same must be for those who are bullied, its happened to another and they understand how you feel.