Andrew Stillman of New Visions Schools is the author of many highly functional Google scripts that teacher can use in their Google Classroom. If you have a Rubric you can automate parts of the grading and feedback process. Goobric is an octopus for Docs!
There are a number of great resources out there.
Here is a list of my favorite Goobric Tutorials
#1 Oli Trussell
@olivertrussell +OTrussell mrtrussell.blogspot.co.uk
Google Classroom, Doctopus and Goobric – The Ultimate Workflow!
Get the Step-by-step guide here: https://docs.google.com/document/d/1D…
I really like this guide:
#2 Eric Curts has a great tutorial here:
http://ti.apps.sparcc.org/videopd/20151006-rubrics-for-docs