When you are using Google Drive Mac users press command and / (forward slash), PC users press Ctrl and / (forward slash), and a list of keyboard shortcuts that work will appear.
Specifically here is a short list of a few keyboard shortcuts that will save you time, but they only work on the Google Drive homepage. Just remember they utilize the shift key and not command or Ctrl.
Create a New Document– Shift + t
Create a New Presentation– Shift + p
Create a New Spreadsheet– Shift + s
Create a New Form– Shift + o
Create a New Folder– Shift + f