They are sure that if any other child plays with a toy they will never get it back. Remove any fought-over toys for a realistic period of time. Set the stage positively, not negatively. Try to eliminate physical punishment. It merely teaches that if you are bigger you can hit.
Some children fight more than others.
Instead of thinking of this as attention getting and negative, give more attention. Let's have a time out. Some days she needed to do this twenty times or more but felt it was a better alternative than spanking, as it taught him an acceptable way to deal with his angry, aggressive feelings. I have learned that if my children are out of control they are usually overtired or hungry. By going home, I avoid pushing them past their limits and keep from losing my temper.