I use Google Drive every day. I'm using it right now, in fact, to write this post. Thanks to The Next Web, I found a handy way to preview all the files in a particular folder.
In the past, if I wanted to take a look at a number of documents, I could click on a folder to view a list of its documents. And from that list, I could click on the documents to open each in a new tab.
A more efficient method is to mouse over a folder, click on the arrow button that appears, and select Open.
This opens a new tab of that folder with a two-pane preview view. On the left is a list of the folder's documents, and on the right are large thumbnail previews of the documents. The thumbnails do not give you much more information than the title, but you can use the arrow keys on your keyboard to go down the list of documents. As you do this, the thumbnails are replaced in the right panel by each document you stop on. You can click into the document to edit it in this view. Just click in an empty space in the left panel to exit edit mode and return to being able to navigate the list of documents on the left with your arrow keys.