My lectures are usually backed by research. A marketing research showed that from websites with similar contents, 94% of people chose the services of the websites that had professional design. 6% chose the websites based on the content.
Clients do not trust the websites that are not designed professionally. And people use services of those they trust.
Even the US government has issued an order that all its websites to be upgraded to a more professional look.
Make sure you hire a professional web designer who is up to date with technology and keep asking her/him to update your website on a regular basis as the codes change all the time. For example two column websites are a big no no these days as they do not show well on mobile phones. And 50% of people who visit your website, do it on their mobile devices.
You will get more clients when you update your website. Trust me!