1. When dining out, you don't have to eat fast food to save money -- just choose a typically inexpensive cuisine. Categories where almost any restaurant's entrees will be under $15 (or even under $10) include Mexican, Salvadoran, Thai, Ethiopian, Indian, Chinese, Indonesian, Korean, Cuban, and Vietnamese. When you need to save money, restaurants to avoid include French restaurants, steakhouses, certain Italian restaurants, seafood, and sushi.
Another nationwide, online source of restaurant data is Citysearch, which has both editorial reviews and customer reviews. You can search this website by location and cuisine to find exactly what you're looking for. Yelp and Chowhound are both good sources of honest, consumer-generated restaurant opinions and are likely to have the scoop on small neighborhood establishments. If you're looking for something more tangible, Zagat guides are the way to go -- but don't pay money for these glovebox-sized books. Zagat guides are compilations of consumer opinions, and anyone can sign up to be on their panel. If you sign up at their website and submit your opinions of local restaurants (which is a very simple process) they'll mail you a free copy of any new book you've participated in when it comes out, which takes place once a year. You can get guides for many major cities as well as a catch-all national guide. I like to get my local book, books for cities I travel to frequently, and the national guide.
3. Avoid dining out on major holidays, especially Valentine's Day, Mother's Day, and New Year's Eve. On major holidays, many restaurants increase their prices and limit their menus. By pushing your special meal just one day ahead of or after the big day, you'll save money, avoid crowds and long waits, and be able to choose any item on the menu.
4. Take advantage of discount programs like Restaurant.com, Cozmo Card, and Entertainment. Restaurant.com allows you to purchase $25 restaurant gift certificates for jusy $10. My Two Dollars frequently posts Restaurant.com coupon codes that will allow you to save even more--I recently purchased $75 worth of gift certificates for a mere $12. Entertainment is a coupon book that you can buy online (or from school kids) that is full of buy one, get one free restaurant deals. Coupons are good for a particular calendar year, which means that if you buy a book towards the end of that year, you can purchase it at a steep discount. Cozmo Card helps Los Angeles residents save money on meals at specified restaurants--you purchase a $30 card which entitles you to significant discounts at various restaurants. Different cities have their own, similar cards.
One caveat: I sometimes find that the restaurants I try using these discounts are subpar. Also, some are finicky about coupons, so make sure to ask your waiter about using your coupon and clarify any special conditions before your visit and then again before you order.
5. Know how to tip. I know the waiters in the audience will hate me for this one, but did you know that you're supposed to tip on the subtotal, not the grand total? Many restaurants trick you into tipping on the grand total by returning only your credit card signature slip showing only the grand total. Most people then leave 15% to 20% of that figure, rather than leaving 15% to 20% of the pre-tax figure. You don't need to leave a tip on the sales tax! Tipping properly can save you a hundred dollars or more over the course of a year if you dine out regularly. Please note that I am not advocating stiffing your waiter--anyone who does their job right deserves a minimum of 15%. If you have the money to eat out, you have the money to leave a proper tip.
6. Share. A dining experience with friends can be a lot of fun, and it can also be cost-effective. Sometimes ordering several appetizers and sharing them can be cheaper than ordering entrees--not to mention that it can be more filling and give you a more varied meal. I'd only recommend this with friends you feel comfortable with, though -- you don't want someone strange eating off your plate, and you don't want someone stiffing you on the bill.With these tips and a bit of creativity, you can easily dine out without spending a fortune.