Have you ever accomplished anything great with an inconsistent effort? Unless failure is considered a great achievement, you probably haven't. You must exercise consistently to get the results you want! It surprises me how many people don't even try to be consistent with their diet and exercise programs and complain about not seeing results. Even the best programs are not effective if they are not followed on a consistent basis.
Consistency is the key. Focus on changing your lifestyle. Do not focus on "dieting". When you focus on dieting, you are looking at this weight loss thing as something temporary. Diets work ONLY to get those pounds off, but what are you going to do after the diet is done? Living a healthy lifestyle is a marathon, not a short sprint.