Paul Julius is an independent consultant who has recently worked with many companies to implement continuous integration at the enterprise level. He also has techniques to measure the effectiveness of CI implementations. One of his favorite metrics is the "cup of coffee" measurement.
The "cup of coffee" metric examines if a developer can get up and get a cup of coffee once they commit code. After they've returned from their coffee break, the developer should have some feedback about whether their code was useful and if they need to start regression testing. Julius says the main advice for CI is to just get started so developers can start learning.