I'd say if you really want to lose weight you should make up some minor goals that are easier to complete which leads to success and happiness.

For example: loose 1-3kg a month or something that is physically possible for any human to achieve.
And when you're starting to notice it works out, you'll be more eager to continue with your diet and after a year you suddenly realize that you went down a lot.

And before you even know it you have forgotten you're on a diet.

And finally I just wanted to say that I don't know anything about diets but I'd say the human mind is the trickiest part.
Peace.