With the stick horizontally in front of you, step over the stick with one foot, then the next. Then step backwards with the next foot, and follow with the other. Basically, you're running in place very quickly, back and forth over your stick. Make sure that you're knees are high.
With the stick still horizontally in front of you, squat down a little and slide to the side of the stick, step forward so you're in front of it, then slide to the other side of the stick and step back behind it. Repeat this so you're really just sliding around the stick, but the squat position makes you're quads do a lot of the work and your constant forward position makes your feet get a great workout.
With the stick vertically in front of you, jump over it with both feet, then again to the other side. It's like you're slalom skiing. Again, make sure that you're knees are high.
With several sticks in front of you, line them up about a foot apart and step forward between the sticks with your knees as high as possible. It's like that drill you see football players doing stepping through tires.