Being honest and being accurate often go hand in hand. However, one can be an honest author, but that does not mean that they are portraying accurate events. When writing an auto-biography, as an author you are only aware of your own thoughts and feelings. To be successful, you must branch out of your own mind and try to see into the minds of the subjects you are writing about. It does not matter whether you know the subject personally or are looking on as a complete stranger. All that matters are your observation skills. For reference:
"I watched her for nearly half an hour-- during all that time she never turned a page, and her face grew momentarily darker, more dissatisfied, and more sourly expressive of dissapointment. She had obviously not heard anything to her advantage; and it seemed to me, from her prolonged fit of gloom and taciturnity, that she herself, notwithstanding her professed indifference, attached undue importance to whatever revelations had been made her" (pg 230).
Reader, I've highlighted in blue my observations and in red my conclusions drawn. Just from watching my subject for only a half hour, I have managed to conclude that she did not like the news delievered to her and placed upmost importance on it. This is an important revelation to the progression of my narrative. Without good observation skills, my story might have had a completely different ending. So my advice to you, is to pay attention and record in detail the events and actions of your surroundings.