What are some useful skills/attributes for being a computer and information systems manager?

First thing is technical skills, you should be technically sound to understand the concept of the work your team is doing. As a people manager, you should have good interpersonal skills. You should be able to communicate properly to the team, peers and management.

You should have some certifications specific to management like PMP, Prince2. These certifications will help you in all perspectives.

Project Management (organizing across a project), attention to detail (roadmaps, milestones, project related execution), ability to align to business goals (ensure the IT/IS systems including uptime, vulnerability/security and data privacy are aligned to the business needs and goals)!

As an IT Recruiter, I know what skills to look for in my candidates to get them jobs!

Technical Skills

In the world of IT/Information Systems, there are many technical skills one would need to know. This ranges from coding/programming languages, methodologies, technical processes, system architecture, security, project planning, etc. Most of these you would learn in school at a college or university.

Interpersonal Skills

As a manager, it's vital that you know how to work well with people. You'll need to prove that you work well on a team and can lead others as well as respond well to your own management. You'll need the ability to communicate well with end users as well as developers. This person will also need to be able to take these conversations and translate the business goals to make a plan for your team.

Other

Because of constant deadlines, you'll need the ability to work well under pressure. Along with this, great time management skills are needed. Good analytical and problem solving skills are important as well.

I think the most useful skill would be people skills. Most manager roles are going to involve managing people rather than computers. You will certainly require a degree of technical knowledge, but I find the best managers know the value of his/her team members and will focus mainly on ensuring that they get the most from their direct reports by fostering a good work environment, and providing transparency and understanding of the business needs so that each person underneath them has a chance to fulfil their full potential.