PREPARING FOR YOUR FIRST RACE
Whether you will be doing a Try-A-Tri race or a longer triathlon, these are a few suggestions that will apply in all situations:
The swim is often the most daunting aspect of a race. The idea of all those arms and legs thrashing around at once can really frighten some people. The best way you can prepare for it is to be confident in your ability to swim the distance. Most Try-A-Tri races start with a 375m swim. That's 15 lengths of a 25m pool. Most people go to the pool and train a bit to make sure they can do the distance before they sign up to race. I suggest that you practice swimming even a bit further, so that you will be in better shape for the race distance. Remember, you have to bike and run once you get out of the water. It's probably a good idea to make sure you can swim 15 lengths straight, but you may also want to do some swim workouts where you do intervals of 50-100m or more, with a rest in between. That will allow you to do more than the 15 lengths in training which will help your confidence and fitness levels.
If you have the opportunity to do an open water swim in a lake, take it. That's the best practice because navigating in open water is a challenge. If you don't have access to a pond or lake, you can practice open water technique by occasionally lifting your head out of the water and looking forward in the pool to sight. Try to get used to doing this while still swimming so that you don't lose time. Another useful drill is to close your eyes in the pool whenever your face is under water. You can open them when your face is out of the water to breath or sight forward. That will give you a good idea what it's like to navigate open water.
It's also a good idea to have a technique or two to fall back on if you get tired or spooked in a race. You may start with front crawl, and then move to breast stoke if you need a rest, or even to floating on your back if you have to. A backup plan like that in the water is comforting.
One technique to avoid the 'panic attack' that a lot of people talk about is to swim the last bit of the warm-up hard, maybe even holding your breath longer than normal, to force a bit of hyperventilation when you stop. I've read that this technique helps to open up the lungs, and you'll be less likely to feel constricted during the race.
As far as the bike portion is concerned - most people are pretty comfortable here. Once again, it's a good idea to do some bike rides that are longer than the race distance so that you'll be confident on race day. Even better is to do what we call a "brick" workout where you do a bike ride and then get off and put on your running shoes and go right into a run. This helps your legs get used to the feeling of moving from biking to running which can be quite strange to beginners. It doesn't have to be a long run, just enough to start feeling comfortable while running will be useful.
Don't over-drink! Most people are too worried about getting dehydrated but that's not a big concern in short races. The body can only absorb 750-1000ml of water per hour, maximum, so if you plan on doing the bike in less than an hour, don't take 3 huge water bottles. I've seen people completely loaded up like they're going to ride through the desert, for a short race in cool weather. It's just added weight on the bike and even if you do drink it all you'll just have it sloshing around in your gut as you run. But be sure to carry enough for your personal needs.
While most people don't fear the run portion of a race (you can always walk, right?) one thing is for sure - you will be more tired starting the run than you would normally be if you just went on a training run (duh!) so it's a good idea to be able to run a bit farther than the race distance. In a Try-A-Try with a 2.5km run, it would be good to be comfortable running 5km or more in training. Even better would be to have run a 5k or 10k road race so that on race day you will have lots of confidence that you can finish the distance.
Another good idea is to watch a race in person before doing your first. You'll get an idea how things flow and you'll see a wide range of competitors which may help build your confidence :) Alternatively, watch one or more of the races on Subaru Triathlon Television on OLN and SportsNet to get an idea how the races work.