Below are two general illustrations of offensive and defensive position on corner kicks. The top image is for a standard 11v11 game, and the second illustration depicts an 8v8 game. There are many, many different variations for corners, I just wanted to provide two standard blueprints for coaches to use or build off of. Please contact me if you want details regarding variations or if you have any questions.

11v11
OFFENSE:
-Player taking the kick should look to pick out an area or spot on the field to play the ball, rather than a specific player (should be somewhere between the penalty spot and the top of the 6-yard box--close enough to allow for a good shot on target but far enough away so that the keeper cannot collect the ball easily. Ball should be driven into the box, not "floated." A driven ball is much easier to redirect into the back of the net than a lofted ball that needs extra power behind the shot.
- Three or four players should provide runs into the box to "frame" the penalty area. These usually include a near post run, a run to the far post, and one to the middle. Players need to time their runs to avoid the ball landing in the area behind them (this timing can be achieved if the player taking the corner kick drops his or her arm just before they approach to strike the ball, signaling the runs to begin). Often, a ball hit long to the far-post will present a great opportunity for the player making that run to head or direct the ball back across the face of the goal in an attempt to find a teammate with a better angle for a shot.
- Usually two defenders hang back to guard against the counterattack. You always want at least one more than the number of high opposing attackers (so if the other teams leaves two strikers high, you would want three defenders).
- At least one player needs to stay ready at the top of the 18-yard box, in case a ball comes bouncing out to that area (this player should obviously look to strike the ball quickly on frame). The other players position themselves in opportunistic areas, either to get a shot or cross an errant ball back into the box. At least one person should guard against a corner struck too far to the opposite edge of the 18-yard box. This could either be a second "holding" player or the far-post run--either way you want to guard against a corner being played completely over the top of everyone.
DEFENSE:
- Usually, a defender is positioned just off the corner of the 6-yard box closest to the corner where the kick is being taken. The objective is to force the player taking the corner into a lofted ball over the top, which is easier to defend.
- A player should be on each post, making the goal mouth smaller. They should be at arm's distance from the post and should be responsible for an area about a yard on either side of them. When the ball is cleared, the goalie needs to instruct these players to release upfield, so as to not keep attacking players on-sides close to the goal.
- You want your best arial defender positioned in the middle of the box, acting as a rover to clear out the dangerous balls served from the corner.
- Each attacking player making a run into the box should be marked. The defender should be sagged off the attacker so that they can not easily run by them. The other holding attacking players should be manned if possible, especially if there is one in or near the goal mouth.
- A striker can hold high, looking to gather a ball for a counter attack or possibly disrupting a ball being played back into the box after it is cleared.
- All defenders should look to meet the ball at its highest point and should clear the ball up and away to to the sides of the field beyond the corner of the 18-yard box. PLAYERS MUST HOLD THEMSELVES ACCOUNTABLE AS FAR AS THEIR DEFENSIVE RESPONSIBILITIES.

8v8
OFFENSIVE:
- More or less the same ideas mentioned in the 11v11 format above, although certain adjustments will have to be made due to the smaller numbers. You probably want three players making runs into the box with a fourth holding on top of the 18-yard box. And make sure you have a man advantage for the defenders holding around midfield.
DEFENSIVE:
- Again, same general ideas that are listed above, although you will most likely want just one player on the post, since you will most likely prefer having an extra player to clear the ball out of dangerous areas. If this is the case, have one person on the near post and the far post player can position themselves in the middle just outside the 6-yard box.

Short Corners:
I am not a huge fan of short corners for several personal reasons, but there are a number of teams out there that like to perform them, and also some of the younger teams might not have a player that can strike a great ball to the penalty spot, so I thought I would quickly discuss the concept in its simplest form. Basically, the idea is to create a 2v1 in order to work the ball in before crossing. All the other elements of the corner (the positioning and timing of runs and holding players) basically stays the same.
When playing a short corner, the player receiving the ball wants to turn to goal (possibly even at an angle toward the end-line), allowing the second player to perform an overlapping run to the opposite side of the end-line. This is necessary because otherwise you will have a 2v1 with the supporting player in an offsides position (specifically if the defending team has their post players step forward to trap you offsides).
After establishing the 2v1, you want to take advantage of the situation quickly in order to get a cross into the box, with the supporting players timing their runs and positioning themselves accordingly. Usually this is accomplished by passing the ball to the overlapping player who sends in a cross.
If you find yourselves defending short corners, and are consistently getting beaten when you send just one player to defend, then you should consider sending a second defender, forcing them into a 2v2. This is the easiest way to disrupt an effective short corner.
Likewise, if you are on offense, you want to try to perform your short corner quickly so the other team doesn't have time to react and reorganize.