CD and then you have selling your programming, something i do all the time, and i think you do aswell.
this is a completely different kettle of fish than product sales, selling someone a hammer doesnt tend to lead to complaints it doesnt fly to japan automatically whilst doing the dishes. *twitch*
selling bespoke software is all about expectation management, and that is a very complex mix of listening and educating.
no surprises im crap at it and tend to need someone with more social skills than myself, im always going to far in one direction or the other and backpeddling.
"shut up and pay attention" is a rule for everything in life, not just sales