What you want to look for is a balanced diet plan which allows you to control your fat intake without being too drastic so that you can keep it up in the long term. Below are a few elements which may be part of the diet plan you are looking into.
Low intake of fats
The question is all fats or just bad fats? This will vary depending on the diet. However, it should definitely cross out foods with saturated fats (e.g. lard). Foods with polyunsaturated fats may be encouraged as these are better for you (e.g. olive oil).
Reduce refined carbohydrates
Most diets say that you should restrict (if not cut out) refined carbohydrates. White bread, pasta, rice, potatoes are all things to stay away from. Instead, opt for brown, wholegrain versions. Reduce your intake of processed carbohydrates, i.e. cakes and biscuits
Lots of fibre
Increase your fibre consumption by eating of fruits and vegetables. Wholegrain foods are also a good source of fibre, which is another good reason to substitute your white bread and pasta for wholegrain versions.
Any lean meat (chicken, fish, lean cuts of beef and pork), eggs, pulses and soya are all great protein sources. Most low fat diets advocate eating lean meat as proteins will make you feel fuller and also provide building blocks for muscle.
Cut down on sugar
This is an important part of most diets! Depending on the diet, sugars found naturally in fruits may be allowed or you may have to restrict your fruit consumption. However, you should definitely stay away from white sugar, be it in your tea, cakes or snack bars.
Substitute your usual snacks with healthier options like fruit, plain popped corn and health bars to stop you eating between meals.
Lots of water
This is important for everybody, not just people following a diet program. Substitute your sugary drinks for water if you can (drinking squash can help you make the transition).
Do not forget physical activity!
The best way to lose weight is to combine both reduced calorie consumption and increased calorie burning, so you need to exercise! The simple truth of the matter is, you lose weight when you burn more calories than you eat, so the more exercise you do, the less strict you will have to be with your diet.
The best way not to get discouraged on any diet it to see progress. Take a picture of you before you start the diet as a reminder of where you started and reward yourself for your hard work!
Do not be too strict!
Diets which are extremely strict lead to yo-yo dieting. Allow yourself some treats every once in a while. Don't completely cut out anything so you don't get frustrated to the point where you will crack and binge.