Prospecting for High Profile Consultants or Agencies

This question is to the leads or owners of high volume consulting or digital agencies. My consulting business is about 1 year and a half old and I still feel like we haven't developed a working prospecting or sales generation method.

Considering the point of inflection for sales/revenue in your businesses, did you find a silver-bullet? If it wasn't just one thing, were there steps or progressions you took towards creating a successful sales pipeline?

If there was one thing you would have done differently or changed early on, what would that have been?

And, is there any other advice you might have for someone in my position?