Weighing your portions with a good scale really helps me with portion size. A lot of foods will list a serving as say 3/4 of a cup and then tell you 140 grams. I was surprised how many foods where the grams and cup size don't match. Some foods settle (cereal) and if you use a cup measure you may be eating more than you think! This is also very helpful with protein servings (chicken, steaks etc...)
Get a good scale (I have a Salter) that will allow you to reset scale to 0 when you put container on scale or after adding food, so that you can add another food, handy when you are say adding dressings to a salad.