Plenty of people have suggested books, etc., and have given you advice. Get the books. Test the advice.

If you want to get good at sales, go back and read Altman's post again (http://blog.samaltman.com/how-to-be-successful). Start with the section you asked about:

4. Get good at "sales"

Notice Altman puts the word "sales" in quotation marks. That means there are other words and terms that you could put in there to increase your understanding. Here are some that he uses: Convincing others, evangelizing, communicating, and believing in what you're selling. Can you come up with some more?

Now ask yourself, for example, "How can I get better at convincing others of what I believe?" What way could you practice convincing someone of something you believed? What would it feel like to convince someone of something you believed? Can you picture what it would look like to be in that situation? What would you need to hear from someone to know they were convinced? Is there any time in your life that you have convinced someone of something that you believed? (Imagine a small child convincing an adult that they believed someone they knew was in danger and you'll realize that a child in this situation knows everything they need to know about "selling.")

Repeat this process with each term. "How can I get better at evangelizing?" "How can I get better at communicating?" (Here he provides some more tips: "Is my thinking clear?" "Am I using plain, concise language?") "How can I get better at believing in what I'm selling?" (Would you buy what you're selling? Have you? Take your reward out of the picture, and find someone who needs what you are selling, and give it to them.) Try with some other terms that you come up with, e.g. connecting with others, understanding the customer's needs, serving the customer, etc..

Brainstorm every answer. The most important thing is that you take Altman's advice and "Show up in person." Test each idea in person, face to face. Engineer situations where you can test your ideas, collect data, and determine what works.

Your problem is not a lack of information. Reading another book is another way to avoid taking action. What you need is imagination, commitment, and a willingness to try everything until you find something that works.

Be patient with yourself. This is a process. It could be a lifetime journey. Enjoy it.