There are a billion ways to organize your stuff. I used org-mode a lot in the past but it’s a bit difficult to setup, especially on Windows. Nowadays, I use a mix of GTD, johnnydecimal.com, Markdown (with Sublime Text), and taskwarrior.org. Don’t forget calendars too (like the one on Outlook) because you can freely add meetings or things to do inside this application.

You have to find something that works for you, there is no perfect solution. You can also ask the same question on !experienced_devs@programming.dev.