Update
Google has streamlined the review process since this was written.
They now recommend that you look up your Place ID and link to https://search.google.com/local/writereview?placeid=<place_id>.
Original Article
Getting reviews in Google helps improve your footprint in Google search results with review content and helps you get shown on Google Maps results. Reviews may even help improve your ranking.
There are a lot of good reasons to get reviews on Google proper. Google even encourages you to ask your customers for reviews, so you’re not going to run afoul of their terms of service running a Google review campaign. Just remember that offering payment or discounts in exchange for a review will likely require some form of disclosure to not run afoul of truth in advertising laws.
The problem is that Google has made it difficult to review your business.
There are some ways of currently linking directly to review forms, but these links often change and become invalid.
The best way of getting reviews is directly through the search results. This lets you give instructions that aren’t going to change greatly as long as Google continues to support reviews.
##Reviews on Google Search Results
To get a review on Google Search Results, you’ll need to ask the customer to search for your site on Google or you can do the search yourself and give them a link to the search results page.
Then, you’ll need to instruct the customer to click on the Write a Review link in the business information box (also known as the Knowledge Panel results) on the right side of the search results.
That’s a couple of extra steps, but it is fairly straightforward.
On mobile, it is a little more complicated with the review system hidden behind a white on blue disclosure caret signalling that more information is available.
And then they’ll need to scroll down until they start seeing stars. No, really, check the screenshot below.
Unfortunately, that’s about the best that we can do for reviews right now. There are other solutions, but they break if you’re not signed in and Google’s been very flaky about supporting review URLs.