One of the most underrated part of triathlon and masters swimming is kicking. But, at the same time, mastering the kick has the potential to completely rework your swim and take you from below average to actually fighting for position in the water. Yes, I know, what you are going to say: “But I need to preserve my legs for the bike and the run.” I agree with you: preserving your legs is important, which is why you need to work on your kick.
By having a weak freestyle kick, you are draining yourself of energy because the few kicks that you are taking require more energy and propels you less than if you had a strong kick. If you had a strong kick, however, you those few kicks will get you just as far if not farther but with much less energy, thus preserving your legs for the bike and run.
There are many factors that go into the perfect kick. What does not necessarily lead to a great kick though is leg strength. You might be able to squat twice your body weight or dead lift your first born son, but unless you have good form and body position all of that does not really matter. When it comes to kicking, form trumps muscle.
A great way to work way to perfecting that form is deep water vertical kicking. Go into the deep end and kick vertically with your hands above the water and WITHOUT fins. If you are kicking properly, your head will stay well above the water. If your form breaks down, then you will sink. See the workout of the week for a good workout to get you started on this.