These are the ways you can keep track of workflow states...

At a glance

On the content, the current state is shown in the workflow status bar

filled circle means you as the current user, are assigned to a content review in that state.

In detail

Learn more about the current state in the workflow popup

In context for the page

See state transitions in context of other actions in the Activity Report - Content

In context, document actions for the current user

See current pending document actions for tasks and approvals in the instance for the current user in the My Comala Document Documents Action Report in the user profile

In summary

Get a summary of workflow states for all content in a space using the Document Managment Report

With macros

Add your own reports:

With search filters

Use workflow filters in Confluence search:

Requires Confluence 5.8 or above.