Most people when starting a new job cannot remember the tasks one after another.. it takes a while to get into the groove of things, and prioritizing things. But if you're unable to get these things down, you might want to talk to a community of people with memory loss and short term inabilities to help keep you on track and find a system that works for you.
I can only speak to what I've seen soldiers do that have lost some memory abilities..
Writing it down, getting good at writing it down, and returning to the written down words often is beneficial. If you really goldfish out on, for example, serving a customer drinks when you stop to show another customer to the bathroom, you may want to start a running tab of things. A small notepad you can attach to a wrist-strap on your arm, for example, to just write "D5" on, then you can show the person to the bathroom, and look at your wrist to help jog your memory of where you were prior to the interruption. "Oh, right, D for drinks table 5.. I was getting those people drinks." It can be as short-handed or specific as you need.
Task lists + daily plans (i.e. checklists of your daily activities at a job that need to be done by certain times) can help as well... but having abbreviated server-style bullet points and short-hands you can easily visualize and whip out on the go would be beneficial for those unforeseeable interruptions.
You gotta know what you're weakest in as well. For me, that's dates/calendar talk. I'm hopeless with it. However, I recently embraced google calendar, and as SOON as an event shows up or someone mentions it, I stick it in the calendar. It doesn't matter if it's tomorrow or 1 year from now. I put it in there. I set reminders accordingly when I do. I also have a widget on my home screen of my phone. It shows the calendar right on it for the day and the next day, so I look at it every single time I do something. Before, I struggled a lot with this, but it's amazing how becoming diligent in the moment "Nope, nope, hold on, let me write it down" can keep me on track a majority of the time. I even schedule FUN things I am EXCITED about, because I have to. Even though I go to Hema practice every single week I still have a reminder. I need it.
Some "higher" jobs don't require that many tasks too... Trader Joes, and Aldi's, for example, pay their cashiers and employees fairly well actually. It's decent pay for the work done, and the tasks at hand are much simpler than, say, a busy server at a restaurant. You can use server techniques anywhere you go though. Nurse assistant's can have some pretty good checklists that allow them to make alright money and take care of patients while heavily relying on a running list of tasks.
For what it's worth, I know a lot of people with varying degrees of what you describe. It will occasionally slip my mind to do a task, but I'm fairly gooda at reverting back to my previous task. I just actively think about the task I was doing right before I start a new one. I know people who immediately forget their patient needed to go to the bathroom if someone stops them and asks where the nearest elevator is. They have to write it down on their arm, and then answer the question, or else their patient will get mad at them for forgetting about them.
To some extent, I would say definitely things like meditation, exercise, focusing exercises, brain stimulating exercises, actively studying and learning about new things, and getting enough sleep all help the brain. I wouldn't be so quick to dismiss them. But if you have a fundamental problem/deficit in the brain (and I have no idea if you do or not) these will not really magically solve any problems.. But they can help a little. I would liken it more to puzzles + alzheimer's patients.. Puzzles have been shown to stave off the more rapid progression of alzheimers.. It gives them more calm, and clarity, and can really help them with being able to focus on a task (the task being the puzzle itself). Will puzzles cure it? No. Will they reverse it? No. Will they stop it? No. What's done is done.. and Alzheimers WILL still progress despite puzzles.. but any tiny and small attribute that will help, we will use.
I find that taking a break from the internet before doing certain tasks helps immensely. I'm not sure why, but it might have to do with the amount of stimulation I experience from the net lingering in my brain.
