Hareem a treadmil can be very helpful. Warm up, and then increase your speed to the highest level that you can run, and keep running on that high speed for however long you can (try 3-5 minutes). Then bring the speed back down to really slow and walk on this slow speed for 2-3 minutes. And repeat.
This techique burns a lot more calories than running at the same speed for the entire duration of the workout.
There is a specific name for this technqiue, I can’t remember, may be Jimmy can help?