One of the most difficult things to accomplish is to get players to make creative runs.  In fact, it seems hard to get players to initiate runs in any way at all sometimes.  Here is a great way to show them that making diagonal runs can get them into good positions to create scoring opportunities.

This is a game with 5 attacking players vs 4 defending players plus a keeper.  The four defenders play as two central defenders (not a sweeper and stopper but two players who will mark up when necessary) plus two outside backs.  The two outside backs are restricted to an alley between the outside of the 6 yard box to the outside of the 18 yard box.  The 5 attacking players have no restrictions at all.  See diagram below for set up

If the outside attacking players (x's) go wide, they have plenty of time and space since the o's can't go out to defend them.  If an X who is playing a midfield role makes a run into the box, they can outnumber the defenders especially since the outside backs can't move to the middle to help defend.  However, if the midfielder just walks into the space in the middle, it would be easy for a central defender to mark two players. 

When the x's start to make diagonal runs and midfielders start making runs through, they start to see how many more opportunities they have rather than being a stationary player.

Next the defense could add one defensive center midfielder to the numbers are now even.  If the x's continue to make creative diagonal runs, they will find that they still remain dangerous simply by making the right runs.

Next, take off the defensive restrictions and if the players continue to make the same runs, they will find they are just as successful as when the restrictions were in place.

The next step would be to add a second goal for the x's to defend and let them play without restrictions.  If they still make these same creative runs, they have truly learned and should be able to apply it in a real game.