Good currency design is:
Hard to Reproduce
You can print your currency on special paper, hide details that copying won't reproduce, or get even fancier.
Easy to look at
Currency units should be easy to distinguish. Make your currency really cool looking, and everyone will want some. Perhaps you print some ethical values on your currency, so that people know what they're getting.
Standardized
The World Game is rooted in the primary unit: the vote. Mark an item in the world game up and you've done the minimal work for the system. This is the unit or "yes".
Four primary denominations:
- "Yes" 1x
- "Wow" 10x the Yes unit
- "Woah" 100x
- "*mind-blown*" 1000x
This should be good for awhile.
Rooted in something everyone values
People appreciate work. That is the fundamental unit: your labor and intelligence. Otherwise you can base it on Earth work, like honey units, or clean water, gold, oil....