Take Baby Steps and Be Realistic
Before even embarking on a weight loss regimen, you should have in mind at least two important aspects: no change will happen overnight, and you won't be able to lose 40 pounds in just a couple of months (not in a healthy manner, anyway).
In other words, it's highly important to begin your diet in the right mind frame. Remember to take baby steps, and to set realistic goals, such as shedding 5 pounds a month, for instance. Having reached those goals will help you stay motivated on the long term, and reach other important weight loss goals.
Don't Seek Out Perfection
You should also forget about perfection! There's no such thing as a "perfect size", or "perfect shape". You probably know by now that perfection is relative and, even more important, unattainable.
Therefore, in order to keep yourself motivated, give up the "perfect" mentality and come to term with the fact that you will most definitely experience setbacks. It's not easy to perform an important lifestyle change - as it is essential to understand that "weight loss" should become equal to "wellness", that is a lifelong change.
So, whenever you feel down because, for instance, you ate something you were not supposed to, take it as such and move on. It's not the end of the world, and it's definitely not worth giving up all the progress you have already made!
Reward Your Victories
Did you manage to lose those nasty 2 pounds this week? Hooray, you should definitely celebrate! Set up a rewarding system in order to keep yourself motivated.
For example, once a week, allow yourself to eat your favorite dessert. Or, every now and then, whenever you enjoy a small (or an important) victory, go shopping, go to a spa, get a massage, a new haircut - whatever makes you feel happy and reminds you that you should be proud of the progress you've made!
Get All the Help You Need
Why not relying on your friends or on any other support system when you want to lose weight? If you can always rely on your family and friends for other kinds of problems, you can bet you can "use" them in order to reach your weight loss goals.
Have a dieting and exercise buddy, call your BFF every time you're upset that you didn't manage to reach a certain goal, rely on the optimism and good advice that come from a specialist in fitness or nutrition. In other words, do whatever you feel is going to help you keep up the good work!