MyFitnessPal'. The biggest part of losing WEIGHT (note...I didn't say losing 'fat'), is maintaining a healthy (500cal a day is a good start) calorie deficit, which basically means eat less calories than you burn in a day. Cardio based workouts will help you burn more calories, allowing you to eat more and still maintain that healthy deficit. Keep in mind that if you burn substantially more calories than you're taking in on a regular basis, your body will rebel and hold onto what fat stores it has. Significantly overweight people can start at a higher deficit than people with 20-30lbs to lose...but in the end your body needs fuel, and food is that fuel. On the other hand...strength/resistance training is MANDATORY for healthy fat (note...I didn't say 'weight') loss. While cardio burns calories...those calories do NOT come from fat exclusively...but also from lean tissue (particularly muscle). Lean tissue is expensive for your body to maintain...and lets face it, how much muscle do you need to walk, or even run? Your body will shed what is unnecessary for your day to day activities. Strength training dictates to the body that the weight you lose comes from body fat exclusively.
During the course of my weight loss, and the three years since...I became a personal trainer. At first it was just for friends on myfitnesspal (its a free site btw...there's no part of it that costs anything to use) who were local to me...then later for others at my gym, place of work...friends of friends lol, etc. I learned as much from training so many individuals as I did from books and research. Each person is different, but the one constant that held true no matter what...male, female, old, young, substantially overweight, or with just a few pounds to lose...is that if you eat enough (more than people usually believe) while still maintaining a calorie deficit...strength train 2-3x a week (low rep/higher resistance is best), and only do enough cardio (walking is best...running is unnecessary and can add stress to joints already stressed beyond limits by carrying too much weight) to help you balance out your calorie intake/expenditure...you'll be more fit than you've ever been in your life, in very short order.
I hope this helps, and sorry for the 'almost' rant, but this is a subject that is very important to me...with soooo many myths surrounding it that its almost sad. Seeing people detoxing, going on crash diets, only eating certain foods, running miles and miles and miles, and overall just working way too hard for no results frustrates me to no end. Eat less calories than you burn, and stress your body with high intensity, short duration work...and the results are flat amazing.
Oh, and if you do happen to stop by MyFitnessPal...my username there is the same as here. Feel free to friend me .