This is the most valuable and important form of advertising you can get. Prospective customers love a recommendation, and existing customers love a bit of service and care.
You should be reaching out to your existing customers at least every three months to touch base with them, make sure they’re happy with the service, and see if there is anything else you can do for them. This in the first instance can easily generate you more business.
In the second instance, if they’re happy, tell them that you’d love to work with more businesses like theirs. Ask them if they will help you do that.
The simplest ways they can do that for you are:
It works well if you offer to do the same for them in return. If a client was particularly happy with something specific that you did for them, you could even ask them if you could use that as a case study for your website.