This tip pertains to all versions of SharePoint and no versions of SharePoint. It is really more of an IIS troubleshooting tip. But we’ll let it slide for today. :)
The extended logging options in IIS can help in troubleshooting issues in SharePoint. HTTP status code logging can help with unauthorized issues and time-taken logging can help in performance related issues.
To enable the extended logging options for all web sites in IIS 6.0, open Internet Information Services Manager and right-click the “Web Sites” node and select Properties. Under Enable Logging click the Properties button. In the Logging Properties window, click the Advanced tab. By default not all of the extended properties are selected, select all of the properties and click OK. For IIS 7 the wording a slightly different. See the images below for more details.