If the error is in a production environment, you can use the ULS Log Viewer to analyze the SharePoint Logs. To identify the error, you can use the Correlation ID as a filter or by grouping values as a treeview. Here's the link for ULS Viewer:
If the error is happening on a development environment, you can enable stack trace to show on the page. This will simply show the error in the page, making debugging easier.
For this, you need to go to the virtual folder of your web application, and modify the web.config file like this to turn off CustomErrors and enable CallStack and AllowPageLevelTrace. You need to do this for each web application that you want to show errors in the page.
<customErrors mode="Off" />
Under <SharePoint> tag
<SafeMode CallStack="true" AllowPageLevelTrace="true">