If you want to get in shape, you will want to exercise on a regular basis. Instead of just exercising every once in a while, set up a regular bigce time for you to exercise and do it every day or every other day until it becomes a habit. The more you exercise the better shape your body will be in and the better you'll feel.
In order to improve fitness levels when biking, try cycling with just one leg. The benefit of this is that you are able to focus on the important part of your leg stroke, that being the even distribution of workload among all of your leg muscles. This trains your leg for the upstroke and allows the minor, smaller muscles to get a greater workout.
If you are new to fitness, start slowly. It may be tempting to push yourself beyond your limits, especially with the enthusiasm that comes with beginning a new fitness regime. Pushing yourself too quickly is the fastest way to get yourself injured, as your body is not ready to deal with the added stresses you place on it. Injuries can sideline you from your workout for weeks, so start with small and realistic goals and work up to more demanding workouts.
Those are only a few of the ways to grasp and maintain the concept of proper fitness. Practice the mentioned techniques at least three times a week and start a regular routine if you want to stay on top of your body's appearance. Nothing is more important than keeping your body healthy and fit.