1. Be Unstable: Use your whole body, and target your core, by performing exercises that engage stabilizing muscles. For this, use an exercise ball, a balance board, a balance disk, or you could simply stand on one leg. Move your whole body while you do cardio. Keep your abs tight while you are moving.
2. Add Resistance: The more resistance that you include with your routine translates into higher intensity and more calories burned. Some tips for adding resistance include: carrying dumbbells while doing lunges, wearing a weighted vest while walking or jogging, or putting a weight between your feet while doing leg raises.
3. Incorporate Intervals: Interval training is an effective tool for creating short yet efficient workouts. Interval training is simply alternating between different short bursts of activity. For example: You can run fast 1 min and then slowly walk for 2 min and repeat this. You can also do interval aerobics, spinning etc.