Hi! This is Charlie.
The first and most surprising feature of "How to Talk to Your Mother" is that it runs backwards. Each section is dated starting in 1982, several years after the narrator's mother's death, all the way back to 1939 when the narrator was born. This technique shows the decay of the narrator's relationship with her mother and then how it evolved over the years. It also makes the story more relatable, as it follows the same order as human memory often does: the from the present backwards. Many of the entries from further back are also more brief, like the second earliest (when the narrator was youngest): "Clutch her hair in your fist. Rub it against her cheek" (94). This brevity reflects the way memory works--it's easier to remember the details of nearer events.
The second surprising feature is the use of second person. Like the timeline of the story, it makes the story much more relatable. The narrator is you, you are performing the actions, and your relationship with your mother is decaying. The story is comprised of your memories.
In addition, the story combines life events like past love affairs, deaths in the family, or her mother moving in, with historical events. Not only do these events often mirror or contrast the life of the narrator, they also add to the feel of the story as comprised of memories. The memories directly connected with the narrator's life are referenced in the framework of historical events and the story itself is a small part of the larger world. The narrator has a fuller, more believable life, connected with events the readers might have experienced or known about.