Task Organization
I tried a lot of ways to organize my tasks over time.
For a long time, I felt like I wasn't doing enough.
Journaling helped with that but not with managing tasks. Also it was a bit
inconvenient because I forgot what I did in the day from time to time.
Here's the system that works best for me currently.

Setup
Have a single todo.md file.
Have three headers:
- Planned today
- Done today
- Backlog

Process
All tasks start in the backlog.
In the morning, move some tasks from the backlog into planned today.
As you go about your day and do tasks, move them into done today.
At the end of the day, move everything still in planned today back into the
backlog.
Then, for each task in done today, read it, appreciate the work you did and
delete the task.

Bonus
- Whenever a task seems too big or too frightening to start with, divide it
into many small tasks.
- If there are tasks you don't need to do and don't want to do, delete them.
- Don't compare what you did today to what you did the previous day(s).
Instead, appreciate the fact that you did more than zero.
- Write as much as you can, even if they are really small tasks like
taking a shower or taking a short walk outside. It's good for the mood! :)
- Never try to "do everything" in the backlog. There will always be things
to do. If you try to empty the backlog, you'll be less likely to divide
big tasks into small ones since that appears to "fill" the backlog.