You lose more weight if you cut your food into small pieces and chew thoroughly. I always used that analogy to explain the best way to introduce change. Smaller, easily digestable, short term goals are easier to comprehend.
Building on these 'quick hits', it gets easier over time to sell broader goals, BHAGs - Big Hairy Audacious Goals, as author Jim Collins (Built To Last) calls them.
On a related note, I found this interesting, a study from my alma mater, The University of Iowa, regarding the impact of small denominations on spending patterns: http://www.press-citizen.com/apps/pbcs.dll/article?AID=/20060221/NEWS01/60221004/1079/RSS01
"It appears that money is not just regarded as a medium for transactions. The denomination of the bill plays significantly into a customer's willingness to spend."