Start with something simple.

Exceeding guest expectations begins with simplicity.
In the fast-casual world the guest is expected to clear there own table and really do not have much interaction with the staff after they receive their meal..
The employee usually designated to keep the foh neat, clean and organized ("nco" are my favorite three letters) does not clear tables nor does he or she pay much attention to the guests experience.
However, this is actually a great opportunity to impress the guest.
Some managers may avoid interacting with the guest fearing a complaint. But, as leaders we do not want those folks to leave unhappy. You are more likely to create a raving fan by fixing a problem effectively.
I simply encourage my hosts to talk to the guest while they are dining and to clear there plates when possible. The reactions are always positive.
When I think good service, I think start with something simple.