I agree with the commenter above me. In my own personal experience losing 30 pounds, taking it slow is the best way to success. Slowly change your diet to less processed foods and more fruits, vegetables and lean meats.
Allow yourself the occasional treat, if you forgo it completely it'll just cause you to binge like crazy later.
Drink more water, sometimes it's hard to do, but drinking water helps clean toxins out of your system and helps you lose weight.
I personally had better luck changing my diet, than with exercise. But I found that if I found things I enjoyed, I was much more likely to stick with it, especially if at first, they did not appear to be something overly difficult. For me this included riding my bike, walking the dog for several miles or playing Zumba on my Wii...which surprisingly makes you sweat like crazy.
Over time you will build up more stamina and be able to do more. You just have to work up to it. I hope this helps you get started and good luck!