Reviews are the modern word of mouth, and word of mouth built every business on your block. Here's a system that works without being annoying.
Ask at the peak
The moment a customer says "thank you, this looks great" is the moment. Not a week later by email. Say: "It'd help us a lot if you left that in a Google review." Most happy customers simply never think of it on their own.
Make it one tap
Google gives you a direct review link in your Business Profile. Print it as a QR code by the register, put it on receipts, text it after the job. Every extra step loses half the people.
Reply to everything
Thank the good ones in a sentence. For bad ones: stay calm, state facts, offer to fix it offline. Future customers read your replies more carefully than the reviews themselves. A graceful reply to an unfair review wins more trust than ten five-stars.
Never buy reviews
Fake reviews get filtered, sometimes get you suspended, and your regulars can smell them. Slow and real beats fast and fake.