2 different categories come to mind.
H&R Block or other tax preparation services.
The second is restaurants. This may seem like a product more than a service but I think it truly falls into the category of service, especially if you look at the national chains. Think Applebee's, TGI Fridays etc.
The reason people go to these places is because of the experience they receive. The franchisors have created a system that generates nearly identical results nationwide.
The first thing you need to do is figure out what makes your service superior to others out there, then you need to figure out how and why this is the case. From there you need to document it and make sure that you have a mechanism in place to ensure compliance.
Granted that is a huge amount of work, but the basic premise is quite simple. You want all of the people you hire to do things more or less the way you would do them.