Avoid at all cost :
- hydrogenated (trans) fat which might still be found in doughnuts, chips, fries. I think they've been removed from
Avoid :
-soft drinks and fruit beverages and most anything filled with simple carbs (sugar)
-saturated fats (lard, fatty cooked meets, or the fat from mammals in general)
Limit :
-white bread, white rice, white pastas
-alcohol
-high fat dairy products (cheese, yogourt, whole milk...)
Consume plenty of :
-fruits and vegetables
-whole grain cereals
-water
Don't skip your main meals !!! Try to eat your 3 main meals and 1-3 snacks. Take in smaller portions as your approach the end of the day or you'll end up with many unused calories that might be stored as fat.
Don't buy into the latest fad diets which are designed to make you lose weight very fast through an unhealthy calorie deficit or the use of diuretics that will make you lose water weight, but soon your body adapts as your metabolism slows, and you hold onto every little bit of fat you can find and it then becomes impossible to lose anymore weight. And since the calorie deficit on these diets is so high, it's unsustainable and as you get off the diet your weight comes back and thanks to your slowed down metabolism you end up fatter than before following the diet.
Don't buy into the "fat is evil" fad either, dietary fat doesn't make you fat, it's the excess of calories over your daily needs that will. Besides, some fats are healthy and essential : monounsaturated (omega-9), polyunsaturated Omega-3 and 6 (those are essential since they cannot be created by the body). You'll find such good fats in : olive oil, nuts, fish, flax seeds... Don't be afraid to consume any of these (within reason, they are still calorie dense !).
If you wanna count calories, figure out your needs (do a search, this has been addressed plenty of times, or use
this link that I just found with Google and have no idea if it's reliable or not), then aim for a 500 kcal per day deficit to healthily lose approximately 1 pound per week. Instead of restricting yourself from eating as much as you want, achieve this calorie deficit mostly by doing any kind of physical activity you enjoy doing (volleyball, soccer, swimming, skiing, running, making the dishes [you'll thank me for this one

]). You can also do half and half between diet and exercise.
Most importantly : don't make it a chore, enjoy a healthy lifestyle ! Having a little piece of chocolate, a glass of wine, a little bit of butter or Brie cheese on your French baguette here and there is not going to make you fat as long as they don't become the bulk of your diet !