It's all about becoming an expert in your particular area of management (i.e. IT, Finance, HR, PM, BP, Exec. Training, etc.). Notice that I didn't mention "general". Jack of all trades, master of none won't get you very far.
I'll give you a tip to take a fast track approach. The tip by itself is very simple, find someone who is already where you want to be and convince them to be your mentor/coach to get there. Of course to do that, you'll need to have excellent communications (required to be successful as a management consultant anyway).
And the best way to convince them to take you under their wing and spend their very valuable time teaching you all they know?
Answer the question this question - what's in it for them and how will you help them get it. Keep in mind that all decisions are made for emotional reasons.
Once you've got the answer, communicate it effectively to them in a way they will understand (there are different communications styles and you'll need to carefully listen to how they speak, and talk their language -- at least if you want them to listen carefully to what you have to offer). Also do check out Management Consulting Firm Blog for some information on how to get to that place soon.
One final thing to keep in mind, once you've found your mentor, focus on what they do brilliantly. Everyone has faults and idiosyncrasies. That's not why you've chosen to work with them so don't let those distract or prejudice you. Stay focused on your goal, to be the most highly respected and sought after management expert in you field of choice.
P.S. As I'm sure any top management consultant will advise you.
- It's about giving not taking.
- Always increase the value of services you provide and the money will come, never the other way around.
- Law of Cause and Effect.
- Money is always the effect of your actions.
- You get paid for everything you do, just not today.