Hello VMTN!
While we have some good documentation on the technical aspects of alert modification, I often get questions on the 'methodology' of alert tuning. And so, I framed up my methodology on alert tuning and posted for the masses:
An Introduction to Alert Tuning:
https://blogs.vmware.com/management/2016/07/vrops-introduction-to-alert-tuning.html
Enjoy!
Mark