vSphere Troubleshooting contains common troubleshooting scenarios and provides solutions for each of these problems. You can also find guidance here for resolving problems that have similar origins. For unique problems, consider developing and adopting a troubleshooting methodology.
The following approach for effective troubleshooting elaborates on how to gather troubleshooting information, such as identifying symptoms and defining the problem space. Troubleshooting with log files is also discussed.