For simple board design projects, I recommend starting with a microcontroller, such as AVR (as used by the Arduino). The chip manufacturer usually provides reference boards as a starting point / cheat-sheet for your design. If you'd like to go deep into embedded system design, I've also accumulated all of notes at: http://bringuplabs.com/guide/smartphone/ I'm actually looking for students to give feedback on this curriculum format, so feel free to message me if you have any questions!