[ericb]

If you had to pick just one?

[melvinram]

If I had to pick one, I'd pick SPIN Selling as feverishaaron said. It's a lot more how to and broken down into steps. Selling to VITO is also step by step, but SPIN Selling approach makes more sense to me.

[feverishaaron]

I would pick SPIN selling from this list, especially if you are selling custom work in an enterprise software market.