Best Practice: Have well defined support levels.
The expectation for application/server support must be clearly defined. When support will be provided: day, night, weekends. How support will be provided: in person, online, phone, etc. To what extent will the application/server be supported and what support the user is expected to provide for themselves. What the user will actually be provided for support.
Best Practice: Have regulary scheduled downtimes and notifications
Usage patterns can be analyzed for your application/server and from them the optimal time for scheduling downtime with the least impact can be done. Keeping these down times on a regular schedule unless usage patterns change will provide a predictability for your users and will help them plan their usage accordingly.
Proper notifications should be posted for any scheduled downtime with an appropriate amount of lead time to allow your users to plan around your system/application unavailability.
Best Practice: Create an admin "cheat sheet"
A document containing common administrative tasks needed to be done/checked on a routine basis should be created and shared with the backup support people. These cheat sheets should also be a part of the overall system/application documentation.