Make sure you have a full list of your bookshelves; you can't organize if you don't know what you're organizing.

Consult each of your bookshelves individually to find their opinion on organizing. Keep track (a spreadsheet is wise) of which are pro-organization and which are anti. If you find any strongly pro-organizing bookshelves, you can get them to help with the rest of this step.

Ignore the anti-organizing bookshelves and work on any borderline cases. Continue until you're sure you have a majority of pro-organizing bookshelves.

You're now ready to get all your bookshelves to sign a library card.