Using a marching motion walk using max velocity mechanics.  Things to look for:

• Effective use of arms coordinated with the legs.

• Lift the knee, and pull the front of the foot to the shin as you lift your knee. 

• Step over the opposite knee.

• Keep the back straight and the hips high.  Don't land on the heel of the foot as is seen in the video a bit.

• Foot should land under the body not in front.