As a consultant you are paid to solve other people's problems.
One of the reasons I became a marketing consultant/strategist is so I could get paid to get good at marketing. I did this after I noticed an interesting trend: almost all the impossibly-smart teachers I followed and listened to and learnt from... were all, or had at some point been, consultants.
Rule #1 is: You only get smarter by playing a smarter opponent.
Consultants tackle so many more problems, and varieties of problems, that they end up exponentially smarter in certain fields than everyone else.
The thing about being a good problem solver is that you need to solve a lot of problems to become one.
Just like becoming a good writer means you have to write a lot.
But when it comes to problem solving, it's a little harder to wrap your brain around it.
For me, it seems like almost every day I am walking around all day trying to figure something out. Something that seems nigh impossible. Thinking about these challenges are the mental equivalent of running full speed, head first, into a brick wall.
But hey, even brick walls break down, given enough time and persistence.