It is the responsibility of the professional to educate the customer on the value he will receive. Unfortunately, in many tech communities (not just WordPress), developers think that demonstrating technical expertise is the way to market. While it can help, you need to speak to the needs of your ideal customer in language he uses. Do not tell him you can write good code. Tell him what business results he will be able to achieve by hiring you. In the end, what the customer really cares about is the result, not the hours it took to write the code.