The most common mistake is what I call under-resting, but is more often known as over training. This is different than doing too much too fast. Make sure you keep the hard work hard and the easy work easy. It is essential that you leave enough time between workouts so that your body can recover. Sleep is the ultimate way to recover, listen to your body. As we progress the workouts will change up to give you more variety.
Never training in open water. As we get closer to your race, I will have you get out in the ocean and swim 2-3 times so that come race day you know what to expect.
Training too much, to fast. You might be excited to do your first race, but if you are new to running especially please do not ramp up to quickly. Make sure you follow the plan to help avoid injury. One of the most common reasons for injury is when people new to running try to run to fast or run to much instead of building a base. It takes longer for the musculoskeletal system to adapt to the unique demands of running. The golden rule is to make haste slowly.
Sticking to rigidly to “The Plan.” I am trying to provide an outline for your to adapt to your life. If you only do 25min of a 30min session the sky will not fall down. On the same note do not cut workouts short just because. Get work done now, enjoy the day later. If you are having a good time riding, keep riding. This should be fun.
Remember that the reason for doing this sport. It should be to keep you competitive, healthy.