Firstly, it's important to know who is giving you the information. Scams and fake diet cures will either cite "ancient wisdom" from some far-flung culture, or else it will have convincing-looking data from one study that was conducted and funded by the company trying to sell you stuff. Any plan that is worth following will have a slew of data and citations from multiple publications and peer-reviewed journals. Now, data can be skewed in many ways, but at least you want to know where the person writing the book/article/website got
their information. Reading over the 3FC forums will give you some good ideas about where to find good resources.
Read everything. Discard plans that promise a quick cure and consider plans that offer lifelong habit changes. Of those, pick one that makes sense to you. There is no one "right" answer, that's why you see so many plans out there and each one has its own vehement adherents and detractors. Above all, it has to be the plan that works for
you. Here are my main criteria:
1. Does it promise quick results, or a lifestyle change with gradual but sustainable imporovements? Anything that promises quick results is a scam to sell you a supplement/meal plan/device for beaucoup bucks.
2. Does the plan include the importance of exercise? Any legit plan will at least bring up the subject. Obesity and overweight are often symptoms of a poor lifestyle, and cannot be treated without addressing the whole lifestyle.
3. Do you like the foods that are included? On any plan you are going to limit or skip foods you enjoy, so it's important to ensure that the foods that are "allowed" are ones that you like to eat.
4. Can you afford to eat this way? Many people forget to evaluate this, but it is absolutely a limiting factor. I would love to go to an all-organic diet, but I gots ta make rent. Meat-based diets like the Primal Blueprint or Atkins won't work as well for someone who is on more of a rice and tuna fish budget.
Above all, read anything and everything you can about everything to do with weight loss. Read (and ignore) stuff you know is a scam so that you know what sort of buzzwords and warning signs to look for. Read every reputable plan you can find; you will find good advice in all of them, even if you don't follow that plan to a "T".
Your needs will change as you lose. What works for you now will need re-evaluation and tweaking as you approach goal. Exhausting, right? That's why you should fill your head with information and tips and advice. 3FC is a great resource because you can get honest feedback from a huge group of people who have tried everything under the sun.
At the end of the day, you may tell people you follow a particular plan just to simplify things. But chances are you are going to be following a combination of 2 or more plans. For example, I tell people I am on a low-carb diet. But in reality, I have combined calorie counting with some of the principles of low carb and Primal Blueprint.
Almost every plan you can think of has a forum or subforum here; most of those have sticky threads for FAQ and resources. If those don't answer your questions, you will find posters who are actually doing that plan and can give you feedback. 3FC is a great resource, so use it! Think of it like Wikipedia for Weight Loss.