Workout Advice?

I have just started a workout plan that consists of kickboxing aerobics 4 to 5 times a week. The sessions lasts from 35-45 minutes. I do not think that is enough to lose my target weight loss of 50 pounds.

Can anyone give me some advice on how to increase the weight loss so I can reach my target goal. I have lost ten pounds so far, but nothing more after that.