I was very bad at this until recently. You cannot think of all your responsibilities demanding your attention in a parallel manner. You have to make a list of

I was very bad at this until recently. You cannot think of all your responsibilities demanding your attention in a parallel manner. You have to make a list of things that needs doing, or you would like to do. Then tackle them one by one. When you are doing something, focus on that and that only. Learn to prioritize. Then go down on your list depending on the priority, but "business" is tricky. Does it require you to handle unplanned stuff and needs dealing with people? Then it is going to be tricky. Also, be aware that, the solution is different for different people. And you should reach your solution through a focused, thoughtful trial and error process. Extensively using some note-taking method helps. Using a tool like ClickUp or Trello also helps. You can also check out the Getting Things Done method deviced by David Allen. There is no silver bullet for your situation. You should try different approaches until you start to figure out what works. And it will take time. From a few days to a few months. And finding a solution to this should be your primary priority.