Have a bowl of soup as a starter. It will help to fill you and is nearly always very low calorie so no matter what you eat after that you will eat less of and so have a lower calorie evening. Soups are a handy lunch too.
Ask if they can serve dressing/sauce/cream in a side bowl and add only what you want.
If you get anything breaded like chicken kiev or with pastry just treat this stuff as a container and eat what's inside it.
Tomato sauces are of course lower calorie than cream ones.
This helps me anyway.