Once you get to the restaurant, if they have the nutritional info listed on the menu, select the low-calorie option. You can also split the entrée with your dining partner or have the waiter box up half in a doggie bag. But do this before you dig in.
Pass on the breadbasket (you can ask for 100% whole-grain bread or raw veggies instead), get the sauce on the side, and limit alcohol and sugary beverages. They add a lot of extra calories. And avoid hitting the fast-food lane like it’s the plague.