While reading a book about teaching children with sensory issues, one section talked about looking for (seeking) the good (positive) things that children do and praising them for it more frequently than focusing on the negative behaviors and disciplining them for it. I've read about this principle several times in many parenting books and agree with it so much that I try to do it with my children.
It has been my experience that children like and need attention from their parents. I believe it helps them know that someone cares about them enough to honor them as a person and that they are valuable to their parents. However, in our busy lifestyles, it is easy to get so caught up in our own personal things that we can forget that our children want our time and attention. So, if they don't get our attention by behaving well, then they get our attention by behaving badly. I wonder if it's because things like screaming, jumping on the furniture, or hitting someone requires our intervention more than playing nicely with others or picking up a toy without being asked.
As I understand it, when you want to help someone continue a certain behavior, you can reward that person each time he performs that behavior and he will continue to do so. If you want to discourage a particular behavior, you can attach a negative consequence, preferably related to the behavior. (I think the technical terms are positive and negative reinforcement. :) )
For example, you want your child to put her toys away when she is finished playing with them. So when you've asked her to put the toys away and she does it, you can praise her and say something like, "Thank you for putting your toys away. You did a great job." However, if you want to discourage toy throwing, when your child throws a toy, you get her attention (to make sure she hears you) and tell her that we don't throw toys and if she does it again, the toy will be put away. Then ask her to repeat what you've said to make sure that she understands what will happen if she throws a toy again. Then when she throws the toy again, you calmly take the toy and put it away and say that we don't throw toys.
I've found that when I choose to pay more attention to the positive things my children do and praise them appropriately, it seems to make my attitude towards my children better and they also tend to behave better as well.