I suspect there are a lot of answers to this question. Part of it has to do with what level of the organization you are coaching/consulting. Consulting at the portfolio and, to a large extent, at the program level requires Business savvy and systems thinking. And the best consultants at that level have the “gravitas” that enables them to connect with executives and senior leadership. That comes with experience and by having had the burden of managing at a higher level. At the team level, there is more of a need for some good technical abilities and a strong commitment to and understanding of Lean-Agile processes.
Finally, you might want to investigate the Coaching Academy. This is for the community of practice of people who want to grow as transformation coaches. Start by looking at the Coaching Academy: Team Level Track.