Here’s a quick tip I picked up during the pandemic and have used many times when playing solo, prepping for sessions, or when writing: use the Pomodoro Technique.
The short version is you decide on a task or activity you’ll work on and then you set a timer for 25 minutes. You work without interruption for the full duration of the 25-minute “pomodoro”. When the alarm sounds, you take a 5 minute break. Repeat. You can do four “pomodoro” periods before a longer break is needed.
This works because it increases the likelihood of getting into the “flow” state during the pomodoro period. It also allows the mind time to rest and assimilate, combine, or otherwise subconsciously deal with whatever it is you’re working on. I find my mind will throw up new ideas and perspectives once I return to the task after the break.
In my experience, I am more productive working in this way. As a person who easily loses track of time when the hyper-focused bit of being ADHD kicks in, it also helps me regulate time and take breaks to speak to family, eat, drink, or otherwise recover.