This list is only devoted to the most important capabilities.

Skills

Electronic design
Requirements gathering
Schematics capture
Multilayer PCB layout
Library creation and maintenance
Low noise analog and low power designs
RF designs
BOM (Bill of Materials)
Component suitability analysis
Thermal dissipation analysis
Mechanical design
CAD 2D and 3D
Research including Internet research
Programming: C, C++, Assembly, Java, PHP, JavaScript …
Processors: PIC, MSP430, ARM, x86, 8051, 68K …
Testing, Debugging and Certification
Validation and conformance testing
Documentation
Standards:CSA, FCC, IEC
ISO 9001 procedures
Project management
Product management
Mentoring

Computer skills

DipTrace, Eagle, Altium, Protel, FreeCAD (3D), SketchUp (3D), TurboCAD, LT Spice IV, Eclipse, Cygwin, GCC, MPLAB, Octave (language similar to Matlab), MS Office …

Test equipment

Spectrum Analyzer, RF Signal generator, Oscilloscopes, Multimeters …

Special equipment

CNC milling machine, table saw, drill press …