Memoirs are really scenes from our lives as best we can remember them. Never through away a freewrite, keep them in a binder, in a drawer, in a box and then use them when you feel stuck.
Woody Allen keeps what he calls his "scribbles" in a drawer. When he needs a setting or a situation he pulls out these sheets of paper and starts to write. You do the same thing. It never fails, you will always win using this method.