I like to say to only assign individual student documents 20% of the time or less. It is SO time consuming to open each students document, even if you use Google Classroom feedback tool.
Drive20
My free Chrome extension will allow you to open 20 Google Docs, Sheets, or Slides at once from a folder in Google Drive.
Google Drive
Open the folder in Drive that contains student work. Click on the Drive20 Chrome Extension and sit back. Suddenly up to 20 tabs will appear right in Chrome.
Control W
Master the keyboard shortcut Control W to close tabs. After clicking the Drive20 Chrome Extension, go to the LAST TAB. After reviewing the students work, use Control W to close the tab and automatically go to the next students document.
Sort Last Opened by Me
In Google Drive make sure your folder is sorted not by title but rather by “Last Opened by Me.” Additionally you want this sorted so that after you open a file that file goes to the BOTTOM.