Below is a cool cheat sheet containing some practically useful shortcuts to use on Gmail. I am not sure how many of you use Gmail but for those of you who do the graphic below can really help you minimize the time you spend carrying out tasks on Gmail.
It does take time to build the habit of using shortcuts and you need to keep trying over and over till you get into it. I personally use a Chrome extension called KeyRocket. KeyRocket for Gmail is the fastest way to learn keyboard shortcuts for Gmail and Google Apps email accounts. It recommends keyboard shortcuts while your work where it matters. KeyRocket informs you, via a subtle notification, when you could have used a keyboard shortcut instead of a series of mouse clicks.
Source : VisuaLeks