Important Note: You must connect your own SPI/ICSP programming header if you want to burn the Arduino bootloader to the MCU. SMD Manufacturing: Need a hotplate and solderpaste Good to haves: - Oscillator Decoupling Caps Expose UART via connector Programming Button Onboard LED Reset Button You don't have to populate everything! Only these are mandatory: Reset Button Find the reference schematic here: https://www.arduino.cc/en/uploads/Main/ArduinoNano30Schematic.pdf