The Seven Habits of Highly Effective People has a chapter that gives several methods of coming up with a personal “mission statement” that’s along these lines. However, the mission statement is FAR more specific, because not only do you detail your goals, you detail the way you’re going to act in order to achieve those goals. Not necessarily the specific steps along the way, but the way you’re going to act.
One of the things to do to understand your goals is to figure out your “roles” (current or desired), like “mother”, “mentor”, “businesswoman”, etc. Then you can attach goals to those various roles: “Good mother”, “knowledgeable mentor”, “successful businesswoman”. It’s not enough just to say “I want to be <blank>”, you should also decide what kind of <blank> you want to be.
Then you ask yourself, “what does it take to be this kind of <blank>?” Once you’ve figured that out, you can write your personal mission statement including ALL your goals and what kind of goals they are. I haven’t written mine yet, but it can look something like this:
Goal 1: Good mother: I will always remember that it’s more important in the long run to teach my child WHY he should behave a certain way than to have him obey me immediately
Goal 2: Knowledgeable Mentor: I will spend time working on my personal knowledge by reading and studying and I will observe the people I mentor closely in order to discover the ways they best absorb that knowledge from me.
Goal 3: Successful Businesswoman: I will develop better relationships with my employees by opening time in my schedule for in-depth conversations about issues that concern them.
The “mission” under each goal can change with the circumstances, as the individual goals are huge abstractions that subsume many concretes, but you’ll always have the overarching goal there to give you direction. I think this method works better than trying to come up with a single, overarching purpose statement, because it’s too easy to omit one or more roles by doing so (either that, or include so much that it provides no guidance whatsoever.) I mean, if I say that my purpose is to write novels (which it is), it completely ignores the possibility that I may also want to get married, have kids, buy a house, etc. However, if I say that the roles I want to fulfill are: Writer, Wife, Mother, Homeowner, etc. then I get a much more accurate picture.