"Work it out."

My kids often fight.  One is upset because another took a toy.  The other is upset because another one shoved him or her.  It goes on and on.  When I was a kid my brother and I fought a lot.  So how do we parents handle our kids fighting with one another?  What I normally do is tell them that we, their parents, will die one day, and then they will have to work it out on their own.  So what I do is tell them to sit down on the couch, or in the grass if it is outside on a walk, and hold hands.  Then I tell them they have to work it out.  Sometimes I tell them they have a time limit.
Sometimes one of the kids in particular may be telling the other how wrong they were (without admitting any wrong).  It is at this point that I often tell them that they must not do it that way.  We do not have this perfected at all.  Sometimes the "work it out" session turns into a crying session that lasts a long long time.  Sometimes it is because it is late.  Sometimes it is because feelings have been deeply hurt.  Sometimes it is both.
Working it out is something that a husband and a wife also have to do.  So a great time to learn this skill is with your brother or sister.  Working it out is at its basic form saying, "I was wrong.  I am sorry.  Will you forgive me?"