This is the simplest and, to me, the most effective way to manage priorities. You already have this program installed and you already know how to use it. It’s called Notepad, and it’s all you need.
Every time you discover something that needs to be on your to-do list, just enter it into a file (I call mine “todo.txt”), and make it easily accessible and open all day. I like to use an outline format for this, using spaces and tabs to indent and make things look nice. You can copy and paste to reorder things and group your priorities by weekday in order to set goals. When something is done, just delete it.
This seems ridiculously simple, there is really no trick to it. But keeping it in a text file gives you complete control over the format, rather than some random program. And keeping it separate from your inbox allows you to set your own priorities, rather than listen to everyone else’s. It’s all about finding what works best for you.