Build daily and weekly habits and routines which lead to a productive healthy lifestyle. “We first make our habits, then our habits make us,” said John Dryden. Consider your life for a moment. You are who you are because of what you do and think on a daily basis. If you want to change your life, change your habits.
Since your triathlon running occurs after biking, make sure you practice running after cycling. Your legs will typically feel heavy despite the fact that you are commonly running faster than you think. The more you practice, the easier the transition from cycling to running becomes. Take shorter, quicker steps to begin, which allows you to settle into a rhythm.
Bike courses vary wildly from race to race; make sure you practice on course conditions and profiles similar to your race. Does your race have steep hills? Tight corners? Long straight flat stretches where you'll need to be in the aero position for long periods of time? Find out and create training routes that mimic the race course.
Swimming well is about efficiency. Beginning swimmers, especially athletes who are experienced in cycling and running, often think they can simply try harder and they'll swim faster. While this works in cycling and running, trying harder in swimming does not work. Because technique in swimming is critical, focus on form over effort.
Make sure you have a training plan. There are many available for purchase, for free on the internet, or you can hire a triathlon coach to create a training plan for you. A plan will give your training the structure it needs and it will help lead you toward your race goals. In essence, it simplifies your training.