Look into disabling unused modules

[TheBen27]

Found some cheap tricks for lowering power consumption; should try them eventually. These include disabling unused modules, turning off the brownout detector, and prescaling the system clock

Clock prescaler: http://www.atmel.com/webdoc/avrlibcreferencemanual/group__avr__power.html
Disable clocks: https://www.avrprogrammers.com/howto/atmega328-power
Sleep with brownout detector disable: http://www.nongnu.org/avr-libc/user-manual/group__avr__sleep.html

[WLaney]

I think those would all be good things to try. I definitely looked at turning off brownout detection at the begining of the project.