1) to get better at selling, one of the first things to do is more practice [1] at selling.
2) there are some skills to learn, and these skills are "soft" ones - which typically receive disdain in techie culture [2].
Last year, I ran for public office. I discovered to my surprise that I interviewed [3] poorly. This explains why I've had difficulty getting hired in the past. I plan to join Toastmasters later this year (when my schedule opens up) to help correct this.
Some books:
Outfoxing the small business owner. Cynical, salesman oriented book. Decent insight into the psychology of many small business owners. http://www.amazon.com/Outfoxing-Small-Business-Owner-Relatio...
E-Myth revisited. We all have cultural baggage about what a business is, and isn't. And for many businesses, that baggage gets in the way of actually getting work done, or getting ahead as a business. http://www.amazon.com/E-Myth-Revisited-Small-Businesses-Abou...
Notes:
1 - If you've got a good feedback loop for yourself, then any practice, good or bad, will help (aka: practice makes perfect). If your feedback loop tends to the same sort of self deception that most people have, then I recommend finding a coach (aka: repetition will cement bad practices, only perfect practice makes perfect).
2 - translation: "dude, you're turning into a SUIT!" (with audible disdaining tone used for last word).
3 - While interviewing for a job, and interviewing in the media share the same name, they're different enough that books aimed at helping one tangentially help the other. But at least I now have a brilliant retort to "what is your greatest weakness?" A: I found that I interview poorly.
Don't change everything you are doing to accommodate one customer, but the best way to sell is to talk to your customers and to be flexible.
People frequently say that sales is a numbers game, and it is if you never change your tactics. You need to refine them as you go. Just keep talking to them, but learn from each interaction.
I plan to take that class this next year.