Don't diet. You are not dieting. You are correcting mistakes in your lifestyle. You never stop that lifestyle. If you can't hack the change you are making then you will not be able to stick to it. This then determines what changes you make to your lifestyle. E.g. drinking more water, taking daily vitamins and omega 3's, planning out an exercise routine and sticking to it, planning out weights/resistance training routines and sticking to them etc. etc. are essential. Eat until you are satisfied, but just eat better foods. OR if you really can't avoid something that would make you guilty, drink a glass of water before that and then add in healthy food with the unhealthy food. E.g. if you really feel like a pizza, make it yourself, load it with baby spinach, fresh tomatoes, mushrooms, etc. try not to go overboard on the cheese and use meats that are processed as minimally as possible. However it you can't avoid those exotic sausages (e.g. chorizo) make sure that you've dumped a tonne of spinach on there so that you can feel good about it at the same time. Then it'll taste great, you'll get the chorizo thing off your mind and you've filled your stomach up with spinach and water so it won't be craving too much of that deadly sausage.
Also tracking your progress with a diary/calendar is quite helpful to look back on how many days of weights/exercise you've put in so you can really pat yourself on the back.