What have you tired in the past if anything? (change of eating habits, excersize, etc) Just changing what you eat day to day will have a huge impact on kick starting weight loss and help you begin to eat healthy as a life change. Also portion size and how fast you consume food are both important.
Any stress or other things in your life that might be holding you back without knowing it? Working out and eating healthy makes a person feel good and want to continue to do better, but when you get stressed or life keeps knocking you down its hard to stay on track because you just don't feel happy. So minimizing stress is essential plus no one likes it anyway haha
I also found that a fun competition with a friend also helps :) Motivation to get fit and stay healthy