Before I begin I will say I've been doing this for years and never been caught and have hit more restaurants than I know how to count. I've had 2 close calls but always managed to get out without issue.
Items you'll need that I call drops:
a pack of cigarettes or an empty pack
a jacket, sweater, bag, none working cellphone, wallet filled with crap, or a found debit card. Basically something you don't care about leaving behind.
You want to hit somewhere that has a bar. Think restaurants like applebees or chilis or a sports bar. You know like a place that has a restaurant area but also has a bar. This is important and key. Going somewhere that doesn't have a bar is going to be a lot more difficult for you to easily slip out and leave. You also want to follow the 5pm rule. Either go when it's at least 2 hours before 5pm or an hour after 5pm. Why? you want to avoid shift changes because you don't want to be there when your server/bartender is ending their shift. You can risk it and hope that the person serving you is nice enough to transfer your tab over to the next person but in my experience 80% of the time they'll ask you to settle before they leave. Therefore I always like to follow my 5pm rule. Also if you go after 5pm don't go an hour before they close, that's just dumb.
Before you hit anywhere you want to case it first from the outside. See where their smoking area is (usually they'll have one of those ashtray poles or something on the wall for cigarette butts. if a place has one of these things you're golden. Look and see how easy it is to duck around a corner and leave. If it's a restaurant that's attached to a hotel that's even better. If you live anywhere near a tourist destination then you'll be eating for free for awhile. One of my favorite spots to hit is a place that's attached to a hotel lobby and the restrooms for the restaurant are actually in the hotel. dashing from that place is as easy as going to the bathroom and walking out the hotels side exit.
So you have your drops and you have your target. Perfect. You go in and don't bother to wait to be seated just say "is it ok if I sit at the bar?" they'll say yes, you sit at the bar. Now hopefully you like to drink because if you don't then this is going to be difficult. But i'll assume you like beer/alcohol.
Sit down, ask for a pint of whatever you want, and a menu. The trick for a successful dine and dash is to be modest. The people you read about in the papers or online that get caught are ALWAYS too greedy. They'll order expensive things and be with another person or a group of people. You HAVE to be modest and on your own for this to work. Order a cheap beer and something midrange in price to eat like a burger or something. Don't go ordering expensive steaks, you're here to eat, drink and that's it.
Be polite with your bartender and server. Make eye contact. relax. say please and thank you. when they give you a beer say cheers or thank them. Watch the TV above the bar. just be polite. When the food arrives eat it. when you're done finish your beer and ask for another. Pull out your drop and your pack of smokes. leave them on the bar. Say you're going out for a smoke. The thing is to go out and leave something there. this is the testing phase. 9 times out of 10 they won't have a problem with this at all. ONE time in all the years I was doing this the bartender asked for a $20 deposit to leave to have a smoke. I shit you not. I paid but that just meant I was going to rip them off for more. Regardless you go out and have a smoke or if you don't smoke "pretend". This is the testing phase to see if anyone stops you, if anyone is paying attention, walk around outside for a bit but don't stay out for longer than 5 min. Go back in, drink your beer, order another, repeat the smoking. I usually go out 2 to 3 times in the span of 2 to 3 hours that I'm there because I'm setting the expectation for my server that A. I'm going out for a smoke and B. I'm always coming back and C. I trust this person enough to leave my phone, wallet, jacket, bag, whatever at the bar.
Now don't drink too much, if you want also order a dessert, but keep the alcohol below 5 beers. It'll be time to make your exit when you're halfway through beer 5ish. Never finish it, just leave half, leave your drop, go out for another smoke and then just leave.
Each time you go out for a smoke extend it a bit. 5min to 10min to even as much as 15min. This way by the time you do decide to dash you have a 15 to 20min headstart before they figure out what happened. even by walking you can get far in 15min.
If you kept the amount under 50 to 60 dollars then you're golden. The restaurant will just eat the cost and it'll be extremely unlikely they'll call the cops. They think you're going to come back for your stuff. ESPECIALLY if you use an old cellphone you don't want anymore that has a sim card still in it. just lock it, they'll assume you want it back. Same with the debit card.
Now you may be thinking "well I can never go back to this restaurant ever again" nope. wait a few months then do it again. The turn over rate for the restaurant industry is insane. Hell I once hit the same place in the span of 2 weeks. There's a tourist destination I hit every single summer on every weekend and i've been doing that for 6 years.
So to sum up be modest, be confident, be polite, and be a smoker. That is how you dine and dash successfully every single time. Good luck.