Really understand what your business is good at delivering.
Be able to juggle wearing many hats sometimes at the same time.
Be excellent with people, most people claim to be but successful owners are.
Ability to manage stress in many forms or have a support network to work thru difficult times.
Recruit well and deliver on your word.
Many more, its a long journey for most people especially if starting with no funding, limited contacts and people in your life saying you cant make it, which sadly is the case often. As you can see many skills needed are more about your character than technical skills.