Being a cheerleader is the same as being an athlete so you should train as one. But instead of just random workouts, how about being specific in your exercises so you will benefit the most as a cheerleader. For example tennis player's workout and train specific to their sport as do other athletes to theirs. Target areas such as your flexibility, strength and aerobic conditioning to help you stay in shape.
There is no way you could be an effective cheerleader without being flexible. Many poses require a good deal of flexibility and you should train for this. In addition to being flexible enough to do the routines, you will be helping to prevent injuries to yourself. You should do at least 10 to 15 minutes of stretching each day if possible. Try stretching in the positions you will do, such as scorpion or liberty.
As far as your strength goes you need to work on your legs for a good vertical jump, your mid section or core and your arms and shoulders. Depending on what your position in the squad is will determine what you might focus on the most in your strength, although a good all round fitness level will benefit you.
For your aerobic conditioning, many will just go for a run a few times a week. To get the most out of your aerobic conditioning you should do sprints, jump rope or any other exercise that will quickly elevate your heart rate. You do not need to make your workout a lengthy process. Get it done and move on.