Is your business flooded with reviews on a daily basis, probably not and it is tough to encourage positive reviews but if you do it right it can benefit you on many platforms.
Using google my business and facebook we are always shown reviews as soon as we search for the business, because google and facebook are keen to show off your reviews and how many you have it's time you encouraged more reviews.
There are a few ways to do this, but making it part of closing a deal or part of a follow up is usually best, capture the customer while they're hot, while they still have that good feeling.