Gmail is widely used for emailing purposes for personal as well as professional use. We devote lot many time to create, send, receive, read emails in day. If you want to manage your emails effectively on Gmail and increase your productivity then you must go thru the official Gmail Guide which claims that you will become Gmail Ninja by reading those help tips.
Gmail team has released this Gmail Tips Ninja Guide where help topics are distributed in different sections. You need to read the document section wise so that you can co-related the basic and advance options.
You may read the document in PDF format and get a print copy of the same of you can also download the document and carry that with yourself. Here is the link for PDF (Printable) format for printing and download link.