When it comes to diets, as with most things. The more you get right, the more chance you have of achieving the results you want. It can be very hard to get everything right from the start, so prioritise the things that will have the biggest impact.

Get yourself into a calorie deficit, if you’re not burning more calories than you’re consuming, you can’t lose weight.
Eat enough protein. Protein is very filling, meaning you’re less likely to reach for the biscuit tin. It will also help to maintain your muscle mass, ensuring that weight you lose is primarily from fat. The exact amount you should be eating varies from person to person, but 1g or protein per 1lb of bodyweight is a good target.
Carb and fat content in a diet isn’t actually that important, once you’re hitting your calorie and protein targets. If you like fatty foods, go lower carb and higher fat. If you prefer carby foods, do the opposite. Just be aware that the calories will stack up very quickly on a high fat diet.