I suspect in some ways, my short-term memory may be shorter than others, especially as I get older. I did not want this to get in the way of my life and so I changed my life around in several ways so as to be able deal with this, and in fact strive.
I eliminate as many distractions as possible, and try to reduce my goals to 1-2 main things per quarter. I am someone who easily gets distracted with cool new stuff. By focusing on a couple of things, I don’t need to hold as much stuff in my memory.
For any important task or note, I write it down immediately. If the task is for someone else to do, I then assign it to them immediately so I can just forget about it. If the task requires a lot of notes or thinking, I still write a placeholder and come back to it later to fill in.
I practice mindfulness as much as I can. In the morning, in the evening, and throughout the day. This helps me from having my mind being to scattered. It helps me to practice single tasking over multitasking.