Kinda ORM so here's some ORM type advice...
This is a job for the waitress/waiter, who is the professional contact from business to customer, and who will be providing most of the "reviewable service."
There are a couple of objectives that need to be explained to the hungry patrons.
First, the customers need to be reminded that they are the most important asset in that building, and nothing would be possible without them.
Then, let them know that their voice is ultimately what helps shape the best possible experience for everyone who dines at the restaurant.
Next, ask them to keep in mind while dining, to look for possible areas of improvement in service.
And finally, ask them something along the lines of = "Would (refreshing description of drinks)___________ or (savory description of appetizers)___________ be a good way to start the day/evening?"
What's going to happen? They're going to be more observant of their surroundings.
The wait staff is going to perform a little better, knowing they're being watched.
You might actually uncover some bottlenecks that could be solved to actually improve the experience.
If shit goes wrong, it's a learning experience, and not a business that doesn't give a fuck.
And then at the end of the dining, have a business card ready to give with their check, with two options.
The first message, "Did you have a great experience? Shout from the rooftops and let everyone know!"
Provide a short link to a landing page that thanks them, and has a list of the top 3 review locations, with direct links to the business' profile.
You'll probably want to create a shortener that ONLY you use. Using Bit.ly and goo.gl are risky, because they have control over it, not you.
Long Example = janesgourmetburgersandsteaks(dot)com
Short Example = jgbs.direct (yes that's the address!)
Below that link, have a message:
"Did you find something that needed improvement? Help us fix it immediately, by sending a message directly to the owner"
[email protected]
Use this on a business card, or cardstock that's small enough to fit in a pocket.
Just make sure it's EASY to type on the cellphone, and the site is designed almost exclusively with mobile in mind.