For example, if you grew up on a farm, you know the difference between the smell of hay and wheat, and certainly that of pig manure and cow manure—because you had to shovel one or all of these at some point. City people probably don’t even know there is a difference. Describing the subtle differences of each and comparing the scents to other scents can help the reader imagine the situation more clearly.

Stick to informal language, unless it’s absolutely necessary to use formal terms. Instead of “utilize” you can just put “use”. Focus on simple language, with one or two syllable words. The only time you should be using higher level language is if you are using scientific terms or describing a technical process. Even then, you should be writing for the average reader.
These memories are also important because they point backwards to what was, and forwards to what was about to happen, with a sense that there was now a new way of seeing these stretches of time. In each memory, moreover, there is likely to be a huge gift – each will reflect a theme, possibly a major theme, which will play out in the rest of the writers’ life.
Create an outline or a graphic organizer of the major topics and ideas you want to cover. For example, you might make a time-order chart -- a chart with event blocks to organize events chronologically. Or, you might draw a cluster web -- a diagram with connected circles -- to divide your autobiography into sections, such as one for relevant background information, one for life-changing events, one for special memories and one for goals and dreams. Focus on reasons why specific events, situations and circumstances were important to you and how they made you feel.