Get your message across and get them clicking your email or reaching for their phone.
In a nutshell -
Design and Function.
Starting with a basic web site is often better. A gradual approach, until you become familiar with the possibilities, unless of course you know what you require from the get go.
Then use your site, get feedback from clients and get new ideas as the web site develops.
You can then improve on its’ functionality step by step.
Your site needs to be focused on its’ target market, be useable, accessible, well maintained, have relevant graphics, strong headlines, directed benefits using simple language, be credible and fast loading.