There are loads of way to organise your collection of banknotes. most will depend on why you are collecting. I organise my one by country a-z but you could use subject or denomination for instance.
By subject could be :
ANIMALS
the above are from
Antarctica,
Congo democratic republic and
Belarus
or BIRDS
from
Singapore,
Suriname and
Zambia
or Women on banknotes ( not very many of them)
from
Slovakia,
Luxembourg,
Italy and
The Czech Republic
but of course there is one woman who are on loads of notes. Bahamas, Bermuda, British Honduras, Cayman Islands, Canada, Jersey, New Zealand, Australia, St Helena, Hong Kong, Gibraltar, jersey, Fiji, Falkland islands, Eastern Caribbean States, and of course Great Britain all have Queen Elizabeth II on their notes:
Other Possibles could be Buildings, Revolutionaries , Presidents, Kings, Queens, Jobs or you could list them as you find them !!!
Finally you could list them by denomination;
Bolivars from
Venezuela and
Bolivia
Dollar from 30 countries from
Australia to
Zimbabwe
I think the rule here is that there are no rules