Speed over size and strength. Coordinators that employ Kiffin-style defenses will often replace linebackers with safeties in order to put more speed on the field. In particular, linebackers must be able to cover receivers; in the Tampa 2 scheme, one linebacker frequently drops back deep into coverage, turning what looks like a Cover 2 defense into a Cover 3. Kiffin's defenses also employ quick, penetrating defensive tackles.
Preventing scores over preventing yardage. A Kiffin coordinator doesn't care how many yards an offense gains, as long as the team doesn't score, an approach known as bend-but-don't-break.
Multiple defenses from one look. Kiffin-style defenses try to use the same personnel (or the same kind of personnel) at all times, so that the offense cannot adjust its play call based on the alignment of the defensive personnel.
Attacking and causing turnovers. Kiffin-style defenses focus on getting the ball away from the offense by stripping the ball away from the ball carrier or reading the quarterback to make an interception. The risk is that if the ball is not stripped or intercepted, then the ball carrier on offense has a better chance of gaining more yards or scoring; the reward is that the offensive drive is stopped without a score more often, frequently giving good field position.