There's an old saying in soccer, that possession is ninth tenths of the law. Without the ball, there isn't much you can do. Watch any big clubs in the world and they make possession a prime goal of their style of play. Sure plenty of team's win games by counter attacking and simply outplaying teams, but having keeping hold of the ball is always of prime importance.
The best modern example of a possession team is Barcelona. They literally pass themselves into scoring chances instead of relying on through balls or wing play. It's sometimes dizzying to watch, but there's a reason why Barcelona won pretty much every trophy there was to win in the past couple years.
Possession is not just passing the ball when its "easy," but knowing when and where to pass. Much of this comes from great communication, but a good chunk comes from one and two touch passing. Granted if you're the next Cristiano Ronaldo or Lionel Messi, then try and dribble the whole opposing team.
A drill that teaches "good" passing is the one and touch possession drill. It's one of the best warm-up drills in soccer, and generally a great demonstration on which players are the playmakers, and which are not.
You will need one ball, at least seven or eight players, and some quick thinking.
Start by dividing the teams into two even groups, and use the 18-yard-box as the field (anything that goes out of the box is "out."). The goal is to possess the ball, that's it. It's the classic game of keep-away, one team against the other. But here is the catch: each player only has 2 touches starting out. You can go anywhere in the 18-yard-box, but you only have 2 touches on the ball.
This means if someone plays you a ball, you have one touch to trap, and one to play the ball: otherwise the other team gets the ball. Starting out can be a bit challenging, as many players are used to taking as many touches as they want. But the drill is great for building a quicker speed of play and making players think about their movement ahead of time.
Once it seems like the players are getting the hang of the two touch, go to one touch! This is a whole different type of game, but it's definitely entertaining. Giving the ball away is a constant, and it becomes a bit of chess game as players try to make the right move.
Another great aspect of this drill is that it teaches decision making. It teaches players to do something with the ball, or they will lose it.