Ask the right questions!
You can be your own worst enemy if you don't ask the right questions before you start any weight loss program. Don't start by asking, "How much weight do I want to lose?" The question should be, "What do I have to do to achieve healthy weight loss?"
The truth is, you don't want to lose weight just to be lighter. You want to look and feel better. You don't want to be winded every time you go for a walk or go up a flight of stairs. You want to look in the mirror and like what you see.
Don't try to 'diet'!
Every time you look at a magazine or turn on the TV you'll see a new fad diet of some kind. The only thing most of them are good for is making money for the promoter. You aren't going to achieve healthy weight loss by going on a diet. You may lose a few pounds in the short term, but you will end up gaining it all back. Dieting starves muscle tissue and that just won't work for any length of time.
Eat good food!
Don't waste your hard earned money on frozen weight loss dinners and protein shakes. Instead, start feeding your body a variety of healthy whole foods. Compile a box full of recipes for healthy, whole food meals before you start, so you'll be armed with everything you need to give your body what it needs achieve healthy weight loss.
Do your research!
Spend some time learning about which combination of foods is best for your body. As a rule, your body needs a mix of proteins, carbs, and fats (yes, fats) to function properly. Learn the difference between, good and bad carbs, proteins and fats.
Start building muscle!
If you want to achieve permanent, healthy weight loss you have to build muscle. A healthy, muscular body will burn approximately 50 additional calories per day, even when you're watching TV. A long term muscle building program will make you feel better, both mentally and physically.
Keep a journal!
Keep a written log of your progress. You'll find it helpful and motivating to be able to look back and see where you were a few weeks or months ago.
As you can see, achieving long term healthy weight loss is not rocket science. You just have to develop a good plan, implement it, and then follow through.