How do you know if your product launch is successful? At the outset, you must know what goals you are trying to accomplish. The right metrics will help you measure - and create - success by aligning everyone to the same goals.
The Plan in Action
Review your vision statement and value definition with your team and discuss what specifically it will look and feel like to people when your product launch is successful. Then decide what quantitative and qualitative measures you will use.
If user adoption is one of your measures, how will you measure it?
If it's increased user satisfaction, how will you measure it?