A good IT consultant has proven authority on a subject within IT. They are subject matter experts and artists all in one. Second, they possess business acumen and management knowledge to stay organized, market their consultancy, and be financially responsible.
To achieve the latter, you might want to take the best accounting certifications out there, so you can rest assured that money won't be a problem. Lastly, they know how to work with people and communicate complicated technical jargon. Remember: an IT consultant needs to have people skills.