1. Dragging Attachments
Simply drag files from the desktop into your message.
(Works in Chrome, FireFox 3.6 and higher, Safari)

2. Selecting Multiple Attachments
Attach multiple files by holding down the Ctrl key (or Command on a Mac) and clicking on each file in turn. Holding down the Shift key will select a contiguous list of files.


3. Don’t Forget the Attachment
Gmail will parse your email for text that suggests you meant to attach a file (“I’ve attached” or “see attachment”) and warns you if there is no file attached.

4. Viewing Attachments Online
The Google Docs viewer allows you to view .pdf, .ppt, and .tiff files in your browser. Just click the “View” link at the bottom of the message.


5. Searching for a Lost Attachment
Gmail’s advanced search operators can help you find what you’re looking for.


A couple examples:

  • To find all messages that contain attachments: has:attachment
  • To find all messages from your friend David that contain attachments: from:david has:attachment
  • To find all messages that have .pdf attachments: has:attachment pdf
  • To find a specific attachment named physicshomework.txt: filename:physicshomework.txt

From the Official Gmail Blog
Original post by Arielle Reinstein, Product Marketing Manager