We Americans love Back to School--memories of a fresh school year complete with new shoes and unknown books. As adults, we love the renewal those memories signal.
Second only to New Years, Back To School excitement lays before us the possibility of pursuing writing dreams again. It has us hauling out pages (computer files), reacquainting ourselves with the stories we wrote ("Say, that's not all bad!"), or remembering how we imagined the tale unfolding.
Now is the time to remind you of the most basic lesson a memoirist needs to learn as this fervor hits: the difference between memoir and autobiography. The forms are different; they demand different strategies from the writer. If you don't understand this, you are bound to make mistakes.
Autobiography is a story where you are basically saying to the reader: I did this, and then I did this, and then I went here and did this, and then this happened, and then I did this, etc. Autobiography starts in the beginning and moves chronologically toward where you are now. You tell all sorts of personal and family history for no other reason than it was formative for you, and it evokes a big lump in the throat.
Autobiography is a fine form; it's also hard to market unless you are a gifted writer who understands how to create drama from the mundane, or writes with an irresistible narrating voice.
A contemporary memoir is a story where you carve out some section of life lived--or choose some series of uniquely related events--and wrap that material around a point you are trying to make.
The point can be as simple as: I did this outrageous stuff, and I still made it to today. Or it can be as complex as realizing, for example, you feel passionate about . . . quantum physics. You can relate key life stories that led you to this devotion. You mix in some research about science, in general, and physics specifically, and voila! the reader learns about the parts of your life that led you to this passion, and about quantum physics, too.
This is a simplification, but the point is crucial: autobiography is fueled by a desire to record all the memorable details of your life. Memoir is fueled by a desire to choose some of those details and show why they are important.
If you don't see that distinction, it's easy to mix up the forms and end up with a memoir that includes a bunch of stuff that doesn't belong there.