As a former NFL defensive coordinator, one of the things I always looked for, after we had determined the tendencies an offense had based on down and distance, field position and formation and personnel, was who were the "go to guys" for the offense.
Obviously our focus was on the quarterback first, then any star running back, then first down receiver, second down receiver and third and short and long receiver. Many times the same player might turn out to be their guy in more than one of these situations.
Attacking a quarterback starts with analyzing the type of protection the offense is using and forcing him either up into the pocket or running him to the side away from his passing hand. Most quarterbacks will want to flush out to the same side as their passing arm. The defensive end or any outside blitz man on that side must guarantee in his rush he stays outside and that the quarterback cannot come out to his side.
Some teams will have the quarterback and the inside receiver work together on a blitz read. The receiver will adjust his pattern automatically to a slant route if he sees a blitz on his side. If it is third and ten and the receiver is tackled for a seven-yard gain the defense has won the battle.
Once you understand a team's protection scheme and blitz adjustment routes you can design an overload blitz where you bring more defensive men at the quarterback than the offense has men to block. Teams that go with only one back and have only six men to protect often find that they are faced with this type of blitz.
The key to taking away a star RB's running game is making certain that every gap is covered and that your support pattern on the outside of the formation is organized and has a quick read.
Defensive teams may line up with eight men to stop the run. They still give up yards if they do not understand that when the offense leads with a full back or a second tight end into the middle of the formation, there is now an extra gap for the running back. The defense must compensate by having a defender on either side of the lead blocker.
Often the running back will become a main target on second and third down and less than seven yards. Teams can take him away by assigning a tight coverage man to him man-to-man even when the rest of the team is playing zone or by shortening the drop of their under zone men so that they can react up to make the tackle and stop the back from making a first down after the catch.
A tremendous wide receiver can be taken out of the game by press coverage by a fast corner and having another defensive back always prepared to help on any deep pattern. Press coverage limits the pass routes a receiver can run and takes away his ability to run well-disciplined pass patterns. This style of double coverage can be accomplished out of zone or man coverage.
A great tight end presents coverage problems in that he will usually be covered by a strong safety that may not have the physical ability to make the coverage. Often it will be necessary to have a backer get a good bump on the line and help to slow the tight end from going deep right away.
There are teams who now only rush three defensive men on third and long and play eight men in zone coverage. If the offense has a "go to guy" on third and long you may see one man out of the eight playing tight man-to-man coverage while the other seven play a deep drop zone coverage.