Consistent kick is a must. Swimmers need to understand momentum and maintain it especially through the break out strokes or the transition between the underwater and swimming. Most swimmers make the mistake of slowing the kick before the break out strokes thus increasing drag and slowing momentum before trying to swim. A consistent kick will help maintain a better body position in the water throughout the swim.
http://www.viddler.com/explore/FasterSwim/videos/253/
Fly kicking on the side helps swimmers understand the importance of kicking both directions with equal force. This will help with working the up kick needed for speed during the swim.
http://www.viddler.com/explore/FasterSwim/videos/254/
Fly kicking off of the wall.
1. Kick immediately upon leaving the wall.
2. Keep you upper body still to reduce drag and focus on a tight streamline.
3. You could actually turn your body slightly towards the wall which will help affect(more force) more water.
4. Kick up and down with equal force.