1) Take 10-15 minutes to list as many childhood memories as you can think of, both big and small. (Here are some categories that might trigger memories)
Family
Relatives
Friends
Enemies
Church
School (First day, worst day, funniest day, last day, etc)
Pets (yours or friend's pets)
Vacations
Sicknesses and Accidents
Celebrations (Christmas, Birthdays, fairs, ethnic celebrations, etc)
Favorite (and unfavorite) foods
Toys, hobbies, games, sports, books
Special Places
Separations (Moving, Divorce, Death)2) Pick one memory that you've listed that has strong emotion of some sort attached (joy, sadness, anger, loneliness, jealousy) Write for ten minutes about that memory, going back to that point of childhood, becoming that child again, writing down the sights, sounds, smells, tastes, "feels." Do not edit, do not worry if what you're writing is "really" true, do not worry about structure. (Sentence fragments, stream of consciousness, all okay.)
3) When finished, reread to make it your own and save in a folder or notebook (or on computer.) This is a valuable deposit in your Memory Bank! Feel free to make a withdrawal next time you need to tap into that emotion, whatever it may be, for a story you are writing!