As of 2022 I have now stopped using OneNote and have my own GTD web app called Hyperpaste that I use for my Getting Things Done needs. OneNote is one of the things I used for awhile and I will leave this post up for reference.
I make a section for my Inbox at the top that is the default location for saved notes that I can enter from the quick entry or from clippings with the OneNote browser extension.
I also use my GTD notebook to hold a Journal of some daily activity. This is not strictly part of GTD but it works somewhat like the tickler file where I can enter dates and things in the future also.
I then put the standard Reference, Someday/Maybe, Waiting For, and Project Plan sections next. Inside those tabs each item has it’s own OneNote page with as much or as little information on it as I need. Often my pages are just the heading and nothing else.
Next are my Contexts. These will be personal to your own work, but @Home, @Work, @Errands, @PC are often popular contexts to keep track of each place you do tasks.
I can easily drag the pages up and down to prioritize them inside each section or between sections to move them out of Waiting For back to a Context or into Someday Maybe or wherever they should go. This is a key feature that makes it easy to use pages to move them around and between different lists as you decide how to organize what you are doing. Moving things out of a Context and into Someday/Maybe or Waiting For or into Reference if you are done with the task but may want to refer to it later.
For an example of how this makes prioritization easy you can see here in my @Grocery list I have the produce listed first since in most Grocery stores the produce section is in the front when you first walk in the door.
I have tried lots of different GTD software over the years from command line scripts, Emacs, Evernote and paper notebooks, but I keep ending up back in OneNote since it is free, works everywhere and has a clipping extension for browsers to save things from the web that I want to refer to later.