Do not justify anything. Do not exalt yourself. Be objective. Speak of people, of things, of the good and the bad, without additions, without deceipt. Relate your experience, what you have done, without using adjectives or seeking palliatives. Bread to bread and wine to wine.
Revise your life from beginning to end. And relate it. Tell the truth. Short chapters, curt. I sincerely believe that you don't know how to write.