Stop eating a lot. If you learn to count calories and learn how many calories a person of your age, gender, and height should eat in a day, you can simply eat less calories than you need. The speed of the fat loss depends mainly on your muscle mass, as the more muscle mass you have the more calories you burn simply existing. Also, your body only takes fat from places it wants to. Working out a specific area over and over doesn't necessarily work off fat in that area.
I personally lost weight by eating only meat and leafy greens. This cuts out all bread, potatoes, nuts and such. I would suggest if you're going to take this route to talk to a nutritionist to see what vitamins you need to take so that you won't get a deficiency. Alternatively, just cut back on the carbs, eat less calories, and stick to taking one multivitamin per day religiously.
I'd like to clarify that I am not a nutritionist, a doctor, a dietitian, or any other form of expert in this field. This is mostly just from experience. I would not recommend working out at the same time as cutting calories, since this will send your body into an extremely low energy state and possibly affect your emotions (irritable, depression, etc.). Good luck!