Below there are some basics of a Mediterranean diet. You can also use a food pyramid in order to eat healthily.
Eat more fresh fruits and vegetables, grains and seeds.
Limit the consumption of animal fat, choose to eat lean meat. Replace it with chicken, fish and vegetable protein. Eat less food which is rich in fat and replace saturated fats with polyunsaturated.
Instead of full cream milk consume nonfat or low fat milk. (except children)
Limit the consumption of food which are rich in cholesterol, like eggs and meat.
Decrease the consumption of refined sugar and other products that are rich in sugar.
Reduce the consumption of salt and don't eat too salted food.
If you drink alcohol, do it sparingly.
Eat the necessary calories from nutrient-rich foods in order to maintain an appropriate weight.