The best generals tend to have a good combination of skills and qualities:
techical: proper education, detailed wide knowledge, experience, intuition, talent, inventiveness
leadership: empathy, charisma, heil, integrity, fairness, magnanimity, generosity, flexibility
personal: curiosity, stamina, energy, valor, mental fortitude, diplomacy, intelligence, wisdom, independence
One can certainly be very successful without having all of the above, but then events beyond him determine if his weaknesses become his downfall or remain mercifully unaddressed. In the end, even the best generals suffered from their weaknesses, albeit to different extents: Hannibal miscalculated, Patton talked too much, Napoleon was too ambitious, Zhukov was inflexible, Washington was too trusting, Guderian was too obedient.