When we write a memoir piece or a personal essay--creative nonfiction of whatever type--, we have a definite advantage over the reader. The story is true, We write it as we remember seeing it happen. We were there; we know exactly what went on, what the setting was and more.
Your reader, however, can see the story only through the words you give them. If you write a sentence like I loved being in Grandma's kitchen., you see her kitchen in vivid detail in your mind. You know that she collected rooster paraphernalia and that she loved the color blue, dotting it here and there around the room where she spent most of her day. You know exactly the smell of that kitchen, the way the light came through the two big windows and the warmth from the oven that always seemed to be baking something. Your reader was never there. You have to bring him/her into Grandma's kitchen.
Don't do it by making a list and calling it a paragraph to show the kitchen. Weave the sights and sounds and smells into your writing so that the reader begins to see that kitchen almost as well as you do. Sounds like a good idea? Sure--but it takes some practice to do it well.
If we write something that we experienced in the past, we know the details but it's all too easy to gloss over them. They are then lost to your reader. When I write that my first grade class marched in line, two by two, to the playground across the street, I know that the teeter-totters were at the north end, near the WWII Memorial, that the swings were on the opposite end of the playground and the trapeze and rings were directly across from them. I know that the building at the far south end was where after-school tap dance lessons were given and I know where the water fountains are located at each end of the playground. I know that the high-flyers and the monkey bars are in the center area. I know that when my class crosses the street to go to the playground, we can see a church on the corner across the street from the playground. I was there. I went there a zillion times, but my reader didn't If I want to give them a sense of place, I need to let my reader see what I already know is there. But I also do not need to tell them absolutely everything.
A word of caution--don't get carried away with giving so much detailed information that you lose the story itself. Too much and you end up boring your reader. Like so many things, there is a fine line drawn and we want to stay close to it, not fall off to either side.
Dinty Moore, author of Crafting The Personal Essay, says that it is our job to transfer what we've seen to the reader. We don't want to leave them with a white page filled with black symbols that mean nothing to the reader.
Be conscious of what your reader needs to be able to see and understand the story you write.