As I look back at my life and career I realize that this is the most important and the most difficult for anyone to do of the 7 habits. As I recall a habit is something you do so often that it becomes part of who you are, yes bad habits can be broken and good habits can be learned. This is why I think this habit is so important, because as educators and as people we need to put in practice what we learned and continue to put it in practice. This is where I think most of us as humans fail, once we learn something we forget to continue the practice and not only that but we believe just because we learned something one time we will remember it forever.
As far as how to teach this to someone else, I think that the best thing to do with my colleague is to discuss what I just wrote about habits and elicit from them about the habits they have started or the habits they have stopped. Have they become habits? If so, how did they become habits and if they didn't why? I would also discuss how in their personal life they have learned a new habit and point out how they did this by practicing and examining their steps everyday in order for this habit to stick.
Finally, for me as I pointed out, sharpening the saw has always been my make or break point on anything. If I sharpen the saw constantly I know I become better at what I do, but if I don't whatever I learned becomes a memory that I will only recall when I need to and though the use of research or looking back at notes.