Sure, you can know the course and conditions, but the actual swimming is important, too. If you don't have access to an open water venue to practice, don't worry. Swimming in a pool is still a great way to train.
In the pool, work on your stroke technique and make it as efficient and smooth as possible. Once you've got the basics down, incorporate flip turns into your workout to prepare for swimming continuously.
You also need to be able to swim in a straight line. Pools tend to have lines along the bottom that you can use as a guide to swim straight. Sadly, there's no line painted on the bottom of the ocean. During practices, try swimming with your eyes closed to see how straight you can swim.
If you're near open water, dive right in. Training in a pool is great, but open water is its own beast. Learn how to navigate waves. Practice sighting, a technique to keep you on course. After several strokes, look up and glance around to make sure you're still swimming in a straight line. Wear your wet suit so that you understand how it affects your buoyancy in the water. When putting it on, give yourself plenty of room near the shoulders so you can rotate your arms easily. Also, practice the type of start you'll do on race day.
On race day, definitely warm up. Test the water temperature, and swim if you can. Otherwise, perform a dry land warm up. Get your body nice and loose -- especially your arms. Do plenty of arm swings, and take a short jog and stretch.
Lining up for the start is one of the most important parts of the race. Be honest with yourself about your swimming skills. If you're not a strong swimmer, don't line up at the front of the pack. You're just asking to be swum over and kicked in the head. Hang back and let the better swimmers start ahead of you.
When the gun goes off, start as strong as you can. Avoid churning through the water and relax into your stroke as soon as possible. The sooner you can establish a rhythm, the better off you'll be.
Even though you've still got the whole race ahead of you, the hardest part is over. Now it's time to have a great race.
Read on for other tips on fast triathlon swim starts.