Strategy
To inform players in all positions where and when to press the player, drop off or hold their position

Organisation
Play an 11v11 match through out the session whilst creating the following scenarios to consider the topic. 

1) When the opposition play the ball wide, how do we mark?

In the diagram below, the ball has just been switched to the opponent's full back. As both our centre forwards are too far away, our left midfielder presses the ball. His run is arced to prevent the early ball to the right midfielder, to instead force him into the middle where we have more support.

The arrows demonstrate the recover runs made to positions inside and behind their men

The diagram below shows how our defence has compacted to cover the middle of the field. Rather than marking our men tight all over the field, we are often marking space, especially when the ball is no where near our player. This allows us to help our team mates when they are in trouble and defend the goal whilst also being in a position to press our opponent should the ball be played to them.

The diagram below shows the position of the Right Midfielder in relation to the opponent's Left Midfielder. By marking the opponent tight, our player is leaving the space he is currently in free for the Left Midfielder to run into. As with all the players, he is inside and behind his man. If he stands too high, the ball may be played over his head. If he stands too wide the ball may be played inside him. The only effective ball to his opponent is now to his feet, which buys us time and must be accurate and powerful or may be cut out. The arrows demonstrate his position between the lines of the ball/near post and ball/opponent.

Here is another example of our player (left back) being inside and behind his man. The easiest way to think about it is to roughly be half way between the line of the ball/near post and ball/opponent whenever the ball is wide of the posts. As the ball is over on his side, the left back is closer to his opponent, so he can threaten him quickly. However, he is still inside and behind his man, to stop the ball being played inside or behind him.

In this instance, the centre half is still between the ball/nearpost and ball/opponent line but is resultantly marking on the outside. This is because he has inside cover and due to the threat of being stretched by the opponent turning outside in such a dangerous area. The other centre half marked MS is the only player apart from the keeper not marking, thus "marking space" in case the ball is played inside either of his supporting players.

This final example demonstrates how the rule works anywhere on the field. Should the striker have marked the centre half tightly, he would be vulnerable to the centre half running into midfield. Even though he is a striker it is important that he is in a position to prevent an easy pass into the defence should the full back have to turn back.

2) When we are outnumbered in midfield or defence, do we press, hold or drop?

When outnumbered in midfield, we are stronger out wide, thus our tactics should change to covering the inside pass and instead pressing the player outside. We will then have the overload in defence. If our wide midfielder is beaten, our full back can then come across to cover, where he should then push inside as at the back we are strong in the middle. If a player has been beaten in midfield to put us in this awkward position, he should sprint back to his near post to recover ground before covering into a position to cover the midfielder that covered his position.

When playing against a 3-5-2, we can follow the similar principle of pushing out wide in Midfield where we are strongest. However, should the player succeed in playing through midfield, the opposite full back should consider moving to defend the wide midfielder should the ball be threatened, but not before, so to have defensive cover.

3) When our wide midfielder pushes onto their full back, how do we balance?

Although the forwards will do their best to prevent the switch to the opposite full back, at times they will be unable to prevent this from happening. Our opposite wide midfielder should always be aware of the switch and looking to anticipate or move early to bend his run to prevent the ball going outside. However the pace of the ball may prevent him cutting off the outside line and a 1st time pass may release their wide midfielder. This will leave a large space for their wide midfielder to run at speed before our full back approaches him. That is unless our full back reads the situation. Instead, he should be anticipating the pass to the opposition wide midfielder and moving quickly up and across to a position inside and behind him. This will allow our full back to press quickly, intercept the pass or make the opposition full back think twice before playing the pass.

4) When the opposition forwards move out wide, how do we cover them?

If the ball is out wide, our full back should be marking on the outside with close defensive cover from the centre half on the inside. If the ball is played in our full back should attempt to make a challenge on the outside, forcing the forward to the inside where we have defensive cover. 

If the ball is out wide and the striker moves wide, the full back should stay on the outside until a point where he is isolated from his centre half in which he should stop and mark on the inside. Although we are allowing the player to receive the ball wide and turn outside, we can not stretch the defence too wide in an area that is not too dangerous. The wide midfielder should also be cutting out the pass as well, which lessons the danger.

If one of the strikers is out wide on the opposite side of the pitch to the ball, he is very little danger, so should be left out wide. The opposite full back should be aware of him by having his body, but not move towards him unless the risky switch pass is made.