What techniques does the author of a memoir use to present facts? to present opinions?

To introduce facts (argumentation): scientific data, previous investigations, references to books, videos or other scholar material.

To present opinions (persuasion): personal experiences, interviews to experts.

Explanation:

A memoir is a kind of text that presents an investigation from a specific subject in order to inform and convince the reader for something; that something will be the memoir's thesis. To make it possible the author has to do an exhaustive previous investigation and then organize all the facts and personal opinions in a structural order. There are some things that a memoir has to have no matter the subject in question:

While writing, the author has to introduce some facts in order to convince the reader about what he is saying; thus, to present facts he or she could use scientific data, previous investigations, references to books, videos or other scholar material, lean on documentaries, historical movies or novels, etcetera; the main purpose is to have hard data and reliable sources that allows him or her to asseverate something.  

To present opinions the author has the obligation to argue and try to convince the reader about his or her beliefs. Trough opinions it could be possible to the author to argue in favour of the main thesis and to make it possible he or she could use personal experiences, interviews to experts, etcetera; the main purpose is, in this part, to have more arguments that supports what was previously said.  

i would lay on the ground, and wait for the earth to simply take me back!

- sincerely, ouma