There are many types of websites, classified by contents, structure, the language of development and more, simple or more complex and, why not, the kind you can make on your own in a few minutes.

But, well done professional work requires some knowledge that only comes with experience.
Many years in this field gave me the ability to understand customers and their targets. My designer background helps me with aesthetics and message communication. And, of course, developing requires some technical skills. It goes far beyond uploading a bunch of files to a web server.  

An effective website has to fulfill many requirements, but the most important is to be visible to the search engines, that is, SEO.