Atmega328p Power Saving Techniques

kentc:
The only pins connected to the chip comes from the AVRISP mkii pinout for uploading sketches.

Then you have floating pins, which increases the power consumption. Either connect all the I/O pins to +5V or ground (through resistors if you like), or enable the internal pullup resistors, or set them to be outputs, or disable the digital data input buffers.