I have two answers.
It depends on whether you've picked a specific field (eg. oil & gas, or fisheries, or biotech.)
If you haven't, then you need some technical skills and some sales skills. The sales skills are important because once you know how to sell, you'll be able to make money wherever and whenever you wish.
The technical skills are valuable because even if you don't open a business in the field you learned in, you'll understand the technician's mindset...and how to learn technical things.
Now if you have picked a specific field to work in, I have a somewhat different suggestion.
If your plan is to become a mover and shaker in a marketplace, you want to plan ahead.
And planning ahead in this case means learning how to MAKE DEALS in that field.
The kind of deals that buy and sell companies, get you new sources of supply, and employ more people.
Get the idea?
You aren't going to learn these things from a run-of-the-mill sales job, and certainly not by sitting at a computer crunching numbers or drawing things in CAD.
You need to get close to, and shadow, an existing company president in the industry.
Am I scaring you yet?
If I am, then you're probably not cut out for this kind of leadership role. Sorry.
If not, then read on.
You might think, "Wait, how can I possibly get close to a president and see how they're constructing and doing the deals in this industry?" It's not impossible. It's not even that hard.
But it takes guts.
I've had employers create roles for me that didn't exist before I showed up on four occasions.
Roll this around.
What does it mean in terms of your possibilities?
You are NOT limited to chasing Want Ads.
You can go out there and CREATE the role you desire.
And there's zero competition there. Everyone else is too gutless to do it!
Imagine...you put your information together on what you want (a role where you're the assistant to the president, so you can see exactly what they do and how they do it.) You are crystal clear and up front about this purpose.
Some presidents are going to be very, very impressed.
And one is going to make you an offer.
It will literally cut years off your career path...maybe even decades.
And this opportunity is there for the taking.
But you have to have guts. Good news: you kinda have to, to be a president.
I read a really good post on TechCrunch today that said if you are doing B2C - there is no value in joining a tech startup and you should just start. http://techcrunch.com/2015/09/13/youve-only-got-one-shot-to-build-a-consumer-unicorn/
The author countered that if you are doing B2B - then there is some transfer-ability and not just soft skills but perhaps industry connections may be useful.
Or you can come work for me, you'll learn how to set up and maintain legal entities. Working for us will provide important legal and financial experience that will translate for you as an entrepreneur in any industry - as you'll always need to form a legal entity and perform basic corporate governance as a the entrepreneur/founder/majority shareholder.
Happy to have you learn on my dime. :-)
Many entrepreneurs start a business because of a passion around an idea, product, or service. They usually have great ideas and can connect that with a customer need or problem. I also see that many entrepreneurs are really good at that passion; but may lack some skills or understand of the "running the business" side of the equation.
An example would be if you want to open your own manufacturing business - have you ever worked in a manufacturing business? I highly recommend working in a business that is similar for at least a year so you learn what works well or what doesn't work well on another person's dime. This is especially true when working with high start-up costs or a very limited initial cash flow which cannot tolerate costly mistakes.
Go work for someone or a business you can learn from is my answer :)