When you begin your swimming training there are many points to keep in mind. The first is relaxation. You may not be very comfortable in the water; you may have bad memories of swim lessons. The swim portion of a triathlon is normally done in open water in a crowd. You will be jostled, splashed, sometimes even dunked and shoved. If you aren’t comfortable in the water, if you feel like panicking when your face gets wet, you will have a problem. So when you begin your training, work on relaxation in the water. Get in the pool and submerge yourself. Stay under the water and look around a bit. Come up for air and go back down. If you feel a little panicky, think about a pleasant place. Relax. The second step is to try swimming under the water a little bit. You won’t be swimming under water in your competition but this step will help in decreasing your anxiety level. Push off the wall and try to swim as far as you can under the water with your eyes open. Come up for air and go back down. Relax. Finally for this portion, go under the water and lie down on the bottom of the pool on your bacd look up. Many times even if you had no problem with the first two suggestions, this third one will cause some difficulty. If you are new to swimming, I advise you to do these three steps frequently all the while reminding yourself to relax, to loosen up.
excerpt from Triathlon Swim Training for Beginners