How do you persuade readers to buy? How much information is good to give away - how much do you with hold to create...

You are asking the wrong question. You should not try to persude customers to buy. That is the incorrect marketing approach.

The first rule of a successful business is do not create a product and then try to persude customer to buy. Rather find an existing need and then create the product or service to fill that need.

Customers hate to be sold. They love to buy what they want/need. If you try to sell customers what you want to sell, you are going to have a difficult time. If instead, you find out what customers want and then present it as the correct solution to their problem, you will be successful.

In order to be successful, you need to get the customer to know, like and then most importantly, trust you. To answer the question about how much information you need to give away, you need to give enough so the customer knows you have the solution to their problem. Do not be afraid to give away too much. Be generous on what you give away. You will build trust. We are living in a very low trust world. People are very cynical. So give away enough to establish yourself as a provider of great information. Remember that people are basically all looking for an easier way to do things. So even if you tell them how to do something, if they see it as a solution to their problems they will want to hire you to provide more detail, to help the implement or to guide them. They basically do not want to do it themselves. They want help, but from an expert. So you must give away enough info so that they believe you are the expert they are looking for.