The basic drill that we run for coaching the finer points of defensing the spread run is called the "3 Man Rabbit". The following videos highlight some of the techniques discussed in Parts 1-3
In the clip below, the closing RDE is late getting to the point of where the RB has dropped his hips and changed direction. He also crosses his feet which results in the RB getting him out of position.
In the video below the LDE gets to far up-field and does not set his edge properly. You never want to have your back parallel to the sideline when setting the edge.
In this clip, the LDE over pursues when closing the gap. He must always have his eyes on the RB as he is an unblocked player and should never get across the face of the RB.
The LDE gets caught "peeking" inside on this play and allows the blocker to hook him and the RB to escape around the edge.
Below are examples of where the three defenders work together properly to defend the sweep.