The primary one IMO is patience. Patience technically and with people. A good majority of the CTO job beyond startups is blending the business and technology and speaking/working with people who have little technical chops.<p>One of the worst traits I see is knee jerk reactions and that extends beyond just a CTO leadership, but it can be horribly debilitating to an engineering team if the CTO isn't calm, focused and deliberate. This is true in small startups and large enterprises.<p>I also believe great CTO's stay current with technology, this of course is a burden and hard to do as the organization grows large. And in this way I think it is harder to be a great CTO than to be a good CEO, simply because change is so rapid and dynamic in technology compared to say accounting. Accounting does have changes and updates but it is not at the pace of technology.<p>I personally think having a wide experience across diverse products, projects and industries also helps a CTO be effective. As companies grow a lot of times it isn't custom development so much as integration of large scale systems which run a business that a CTO has to be effective at getting integrated. The challenge there is rarely one of technology but one of negotiations with other executives and getting stakeholder by in. For the longest time CTO's have been stuck at the kids table when it comes to the C suite in larger organizations, this is starting to change for the better but it is still true in most large enterprises. So a great CTO has to develop superior people skills to be effective, IMO.