You can organise the projects on your My Projects dashboard by tagging them. Once you've created some tags, a list of tags appears on the left hand side of your dashboard, which you can use to filter by tags (just like directories / folders).
To tag a project, click its menu dropdown on the right hand side of your My Projects dashboard and choose Edit Tags. Type any word, such as "book", in the box to create a new tag. Click the X to the right of the tag name to remove a tag.
Here's an animated GIF to help you see how tagging works: