It should be considered a treat to go out to eat. Each person in each place will have different preferences for going out to eat: how expensive the restaurants they prefer are, how often they go out to eat, and if they even have a set budget for their dining-out habits.
 
The best advice to give in regards to dining out is to set some ground rules, varied upon each person. Set a weekly limit to how often you go out. It is easiest to set specific days to dine out (such as Saturday nights, Tuesday lunches, etc.). If you have a regular routine to follow, it will be less likely to break the routines and go out more than planned for. 

Budgeting your costs is also crucial to dining out.  Go with a set amount of money, preferably cash, so you do not overspend while caught in the moment of dining out. If there are two of you on a date, or if there are five of you in afamily, set a specific amount (whether per person or for the collective group) and make sure you do not exceed that amount during the meal.

Search out restaurants that offer daily specials (such as lunch specials or early bird dinner specials, etc.). Also search for coupons to various restaurants. Coupons such as “buy one entree, get one free” are always a good sell; these coupons can be found in local newspapers and in coupon books.

When you are not treating yourself by dining out, it is a good idea to pack a lunch for work and to cook a good and inexpensive home-cooked meal for the evenings.  Maintaining a set schedule and limit for how often you dine out and how much you spend will save you plenty in the long run.