Books listed here are not specifically geared towards memoir writing; some of them are even explicitly addressed to fiction writers. However, the craft of story telling is very similar, whether the story is "true" or invented.
Natalie Goldberg: Writing down the Bones
Not a textbook style manual at all, these nugget-sized lessons pack a transformative punch. Five tiny paragraphs on verbs (The Action of a Sentence) alone might enliven your prose, opening doors you didn't know were there. Goldberg calls this being "awake to language". But, rather than about prescriptions and rules, the book is about freeing your voice, delving deep within - about awakening to language as a way to awaken to your self. The entire book feels zen, reflecting the author's claims to kinship between writing and meditation. So, if, rather than for a ten-step writing program, you are looking for a string of two-minute inspirations, like beads on a buddhist mala, this is a great book to keep nearby.
Anne Lamott: Bird by Bird
Non-technical advice on the process of writing and how to get out of our own way, delivered through fast-moving humor. Lamott's chapter on Shitty First Drafts has become a classic, but her exploits on Radio Station KFKD alone make the book a worthwhile read. Beyond much about how to get words onto the page, the book delivers lively insights into why publication isn't at all what you might imagine it would be. Finally, Lamott convincingly portrays writing as a communal process: the why and how of writing with others, and, above all the conclusion that the strongest writing always is for others, a gift for friends and strangers in calamities similar to our own, a way to give back to a world of authors who comfort, restore, and clarify our path, a way to use loneliness to feel and help others feel less alone.
Ursula Le Guin: Steering the Craft
If the task of the writer is to enchant, to create a dream from which the reader will not wake up until the story runs its course, then Le Guin ranks among the finest enchantresses of our time. In this slender volume, she lays out the secrets of her prose: what it means for language to be "gorgeous" with sounds, to mirror plot action with rhythmicity. Her explanation of point of view clarifies a concept obfuscated in many other guides. Understanding the magic of creating words and verse through her explanations and beautifully selected examples will do much to free your own movements across a page and awaken you to become a connoisseur of language well-crafted.