Original post by Luke KostanjsekPeople post all kinds of crap in these sort of threads (and would appear to have done so again) so I'll try and give some information without the nonsense.
Firstly, avoid fad diets. Whilst plenty of them will help you lose weight, they are not a good way to go about it, Two problems. Firstly, they aren't healthy. They normally involve cutting out food groups, or fasting, or some other rubbish. These are not particularly good for you. Secondly, and more importantly, they aren't sustainable. Sure, you'll lose a couple stone in 6 months or some such. Great! But then, almost invariably, you'll fall back on old habits and the weight comes straight back. If it isn't sustainable, it isn't a long-term solution.
So, in terms of how to manage your diet. Make some kind of measurement (a rough measurement is fine) of how many calories you're taking in. Losing weight is pretty simple really. You simply need to be using up more calories than you're taking in. If you're a guy then the average calorific requirement is about 2500, if you're a girl then it's about 2000 (I think). This varies depending on your activity level, there're calculators online to tell you your calorific requirement. Then, to start with, just subtract 300-400 calories from this, and that should be your daily intake. You can increase this as you get more comfortable with eating less (I'm cutting at the moment, and I'm about 500 calories below my requirement).
In terms of what you eat, strictly it doesn't matter. If you're taking in less calories than you're using, you'll lose weight. However, if you're eating less, in order to meet all your other dietary requirements you'll want to stick to healthier options. Typically, I'd recommend sticking predominantly to white meat and fish, lots of fruit and veg, and something like weetabix or porridge for breakfast. I find it's easier to stick to this kind of plan if I have a cheat day, where I'll loosen up on the dietary rules.
Also, add some exercise into the mix! Some form of cardio would be the way to go. Start off taking it easy. Go for a 20 minute run, cycle for an hour, something along those lines. No more than twice a week to begin with, then start to increase it as you feel comfortable.
That would be the most basic advice I could give you. Good luck!