stop eating. You'll lose weight. For fat, ketogenic seems to work really well for me. I'm inhaling cheese sticks, 1-2 every hour, low in carbs and high in protein. I'm basically living off lean lunchmeat, protein powder, and cheese sticks. High-weight low-rep lifting also shreds calories and is great for your body. I'd rather slam heavy weights for an hour and burn the calories over 2-3 days than do 2 on a treadmill.
Cardio is great in the gym, but it's a relatively limited method of losing weight. My personal method is to work out on treadmill for a very short period--in some cases 5 minutes--to build up your heart rate and get your body adjusted, then lift hard and fast. Explosive lifting, alternating muscles for rest (like "5x squat, 8x curl, 5x squat, no rest just alternating muscle groups...I literally bring dumbbells over to the squat rack). I'll get flamed for it, but I prefer using the rack for squats and benches, since you can go a bit harder/heavier and still be safe. Either way, when I've done this, my heart rate stays up that entire time I'm lifting, especially if you drink caffeine while in the gym, and the after-workout burn feels higher and seems to be better.