There's really not much to be said for the calendar, except that there must be One Calendar to Rule Them All.  You can use Google, or Outlook, or iCal or a paper solution, but you should only be keeping one master calendar.  Otherwise, you invite chaos.

My Implementation

I personally recommend a web-based calendar such as Google's solution, because it allows for cross-device sharing and integration with great services like Doodle .  If you are using iOS, I suggest Fantastical , which integrates with the iOS calendar and is the smoothest App I've found so far.  On MacOS, I use  Fantastical.  I haven't used paper in a long time, but when I did, I loved Franklin-Covey .  Their binders and fillers kept it interesting.

Secondary Principles this Tool Implements

  1. One Calendar to Rule Them All
  2. Deal With It Now
  3. File and Forget