I think a fundamental question is are your trying to sell something specifically, or are you interested in selling as a career and trying to figure out how to go about doing so.

While I agree getting out there and just doing it can work, I think the basic elements of sales that can be learned in a short period of training (and cut down the learning curve) - when I first started selling it was Xerox's sales training, and there are many more options available today, but these course teach the fundamentals of sales, which are definitely a critical part to success in sales (ie - you have to ask for the order, listen for objections, learn to overcome them, etc).

There is another part of learning to sell that is not easy to learn, and my experience is some people have it and some don't, and if they don't you can't teach it. This is the way you intuitively listen and understand customer's needs, know when to ask questions, know when to shut up and listen, and when to close the deal. I have been out with many sales people over my career. Some are genius when it comes to these elements. Some can't figure them out after years of experience.
Good luck and if you want to talk more about this, let me know.