The first-month experience for new customers being onboarded is one of the most important things for agencies to work on optimizing and making more process-driven.
If you really knock that first month experience out of the park, set the customer's expectations properly week after week, execute some early wins, and deliver on time within 30 days, a number of things happen.
Remember - the customer has just paid a lot of money to get started with you. This validates their decision. They are thinking "I was unsure if it was risky to hire this firm, but now I know it was the right choice. I made a smart decision"
And then they go out and rave about you online and you're only 30 days in. And it becomes a referral engine.
The other thing that I noticed is that sometimes it's out of your control that things are going to be a little bumpy in the first couple of weeks. Things can go wrong. In a services business, sometimes things are out of your control.
But if you managed expectations perfectly week after week, that's literally the difference between a new client who is going to work with you to make it right vs. a client that's thinking "if they make one more mistake, we're done."