1. Really read the menu. Avoid dishes that are fried, breaded, creamy, dipped in batter or sauce. These items are usually high in calories and unhealthy fats. Look for words such as "steamed"or "broiled" or "boiled". Choose tomato based sauces over cream sauces. Don't be afraid to ask how something is prepared if you aren't sure from the menu description.
2. Don't be afraid to ask the waiter/waitress to have the kitchen hold the sauce or put it on the side. Many dressings and sauces are high in fat and calories. By having the sauce or dressing on the side, you are in control of how much to add.
3. Many dishes wouldn't be so unhealthy if they were better prepared. Special order and ask questions. Don't be afraid to ask for "no butter" or to have something steamed rather than deep fried. Too often a side order of broccoli or spinach with be served swimming in butter or sauces which makes your healthy veggie not so healthy.
4. Remember to take your time eating. Chew your food and enjoy every bite. It takes about 20 minutes before your brain gets the message from your stomach that you are full. Put down your fork between bites and talk with family/friends.
5. Order water over sodas and juices. Don't drink your calories! Most sodas and juices are loaded with sugar and calories.
6. Some restaurants have a "healthy" section on their menus. Usually these items have less fat/calories, are better prepared or are just smaller portions. Try to choose from this section but don't be afraid to still ask questions or make a special request.