Step #1: Eliminate the U.S. Penny ($0.01) Coin.
Step #2: Replace the U.S. paper Dollar ($1.00) with a U.S. Coin Dollar, universally.
These two easy, if unpopular, changes would save billions over a 10 year period, would bring the U.S. in line with other nations currency styles and uses, and really is one of the easiest no-brainers going.
What amzes me is that it will probably never happen.