The pilot's failure to properly follow pre-takeoff checklists (resulting in the engine starters remaining engaged after engine start, generators not being activated, discharge of the aircraft battery and consequent total electrical failure during flight with associated disabling of normal landing gear extension capability), and his subsequent failure to properly perform a manual landing gear extension resulting in a landing with the gear not down-and-locked. Factors included: the pilot's lack of experience in type, steps not listed in the manufacturer's Airplane Flight Manual (AFM) GENERATOR INOPERATIVE procedure, conditions not listed in the manufacturer's AFM MANUAL LANDING GEAR EXTENSION procedure; and the FAA's inadequate approval of both of these procedures.