I would take a class like the Dale Carnegie sales class. Really excellent fr enterprise sales, but when I took it the students included two guys opening a T shirt stand on Cape Cod (sales cycle less than 2 minutes) and a saleswoman from KLA-Tencor (sales cycle between 18 and 36 months), a salesperson for ADT, etc. One of the most useful courses I've ever taken.

And for enterprise sales there's a whole vocabulary and model to learn: your coach, understanding who has the signoff, when you're talking to someone who will waste your time -- and when someone who seems insignificant but is actually the decision maker, how to structure the deals. And how to hire, manage, and incent (mostly but not exclusively financially) them.