The first partner he had in the biz was frakkin' Woz. Woz is a titanic genius engineer, 99% of the people who've ever even viewed HN would naturally draft behind him (especially back then).
From there, SJ saw that he could have more impact driving engineers to achieve a vision than he ever could soldering or programming.
He had an uncanny ability to know what customers want. He was the customer and knew what would sell. He fine tuned that skill away from Apple during his hiatus so when he came back he knew how to turn the company around as the industry was changing right then. It's also about being in the right place at the right time.
he was very clever; very smart - one of the smartest people I've ever met; he had pretty atrocious manners; and he didn't really "design" but rather reacted to a design, he had a very clear sense of what he thought was elegant, clean and clear; he never said "let's build this", he'd say that's crap, make it better; he'd say it's a beautiful birthday cake inside (the ideas within a product) but you've covered it in dog shit frosting (bad UI); his intuitive sense for clean design and clear usability was awesome. (and yes Woz is/was an enormous brain; able to "think in electronics" and express complex things with hardware) you will pry his company's products out of my dead, cold fingers; and he taught what it means to truly hate another human being.
From there, SJ saw that he could have more impact driving engineers to achieve a vision than he ever could soldering or programming.