Art of Defending -- As in football, basketball, ice hockey, and other sports, sometimes a team can experience a huge "lift" from a great defensive play. In college and in England, I remember being more fired up about great tackles as opposed to goals or one-on-one moves. Try and instill a sense of this in your team. If they need some motivation, email them this link: http://www.youtube.com/watch?v=tRSzSNfTPvk&NR=1. Although we like to encourage patient and composed defending for the most part, and despite the fact that in Montana we are generally not allowed to play soccer as physically as in other parts of the country or world (i.e. England), this video will get any defender's blood pumping.
As far as exercises, here are two simple games to encourage good small group defending. Jeff Bookman is a phenomenal coach in Chelsea's youth system, and these exact drills are often done at the college and professional level as well as with younger ages.
http://www.insidesoccer.com/is-web/movie?id=342
Although it is a little confusing, the objective in this game is to get the ball from the player at the top of the diamond to the one at the bottom of the diamond, or vice versa. For older teams, explain to the players on offense that they will be most successful if they move the ball quickly with one or two touch play (this also pressures the defenders to be quick in their organization).
http://www.insidesoccer.com/is-web/movie?id=343
Explain to your defenders that the idea is to pressure/direct the ball into defensive support. For the older ages, demand quick ball movement (one-touch passing allows the players on offense to split the defenders easier) and quick defensive positioning. You can also divide the players into pairs, cycling each pair into the defensive role, and see which team allows the fewest goals (the ball going from one end to the other) in a certain time limit.
Defending & Fitness -- http://www.insidesoccer.com/is-web/movie?id=192&pro=1
This is a great fitness game. It also emphasizes good possession. When a player is tired, the first two things to go are the mental awareness and his or her touch, so encourage the offense and defense to focus on maintaining both. I think this works best with FOUR players on offense in each grid (the number of grids will depend on how many players are at practice). Also, you can add space in between each grid if you want to achieve further fitness. Note how the defenders have to go through all the grids TWICE without stopping before rotating in a new pair. Also note how there is a gate, made up of two orange cones, that the defenders are suppose to go through after they run the length on the outside and before they enter first the grid (this is done correctly at the 2:02 mark in the video).
Transition -- http://www.insidesoccer.com/is-web/movie?id=317&pro=1
This is a great exercise for players of all ages, as it promotes the essential concept of transitioning in the flow of play. In the game of soccer, a team has a huge advantage if they can transition quickly, specifically from offense to defense and vice versa, as they stay much more organized as a team. This ability usually translates to more attacking/scoring opportunities for your team and less easy chances for your opponents. But this concept must be embraced and executed by the players--it cannot be something achieved by a coach yelling from the bench (much like most other soccer tactics). The best part about this exercise is that the pair that "falls asleep" suffers and the teams that stays mentally sharp benefits. As a coach, have a number of balls ready for quick restarts in order to promote the fast pace, up-tempo action, and quick transitions.
Possession, Scoring & Defending -- http://www.insidesoccer.com/is-web/movie?id=570&pro=1
This is a great conditioned game that incorporates a lot of soccer concepts and creates an environment that allows for many scoring opportunities in order to practice shooting and attacking. In the video, Valencia's reserve team uses the entire half of the field for this game, however it can be performed in a much smaller playing area. I like to play on a field that is approximately 30 yards long and about the width of the 18-yard box. I love playing with two large goals, however if you do not have such access, they can be substituted with smaller goals (without goalies if need be). The emphasis for the team in possession should be to move the ball quickly in order to exploit the find gaps in the defense, thus creating scoring opportunities that MUST be taken quickly (this game punishes the player who takes too many touches in front of goal which is why I love it so much). The team on defense wants to stay as organized as possible and transition quickly after winning possession. Note the touch restrictions explained in the video (two-touch for the players on the field and one-touch for the neutral players off the field). This is the standard we should strive for with all of our older teams, and although the restrictions might might be tough with some of the younger teams, we should still be emphasizing quick ball movement. In the video, the Valencia coach lets the teams play for four minutes before rotating them out with the neutral team on the outside. I often like to modify the game so that when a team scores a goal, they immediately get the ball from the goal or goalie that they just scored on and they attack in the other direction. The neutral team hustles on to take the place of the team that just got scored on, who becomes the neutral team on the outside. This way, the players on the outside are always involved as neutral players, however they must be ready to quickly defend the appropriate goal after a goal is scored.