Growing up I recall having a fantastic memory, really sharp, but later in life even much before diagnosis I had become held back by my poor memory. I still to this day have a terrible memory.
That being said I do make efforts to try and improve it, and it has helped.. Just have a long way to go still.
The key thing for me was to find out a way for me to remember things, and use that exclusively, for example:
I use my visual memory now when I want to remember product codes in the shop I work at, just 4 digits but for the life of me I can't remember them, unless I take a mental photograph of it - I can hold that visual in my mind just long enough to type it into the computer. Once I do that, I find that I can remember that number for a few minutes sometimes when I need to, or postal codes too.
Lately been playing with memory palace technique, trying to memorise playing cards.. But things loved ones say will surely be lost - I hope that gets fixed some day because I infuriate my girlfriend.