There are numerous companies out there providing professional designed web templates. There are also site that offer free web templates. Then off course, one cannot expect all the free web templates available on the web site are professional, there are however, some free web templates are designed professionally and optimized correctly. If one is seeking for more professional service and support, one can opt in for premium web templates company. An example will be DeonixDesign where the company offer thousands of professional templates. DeonixDesign work as after user subscribe their service, they can have unlimited access to all the contents available there.
The two main parts of a template are the content management code and the theme. These should be kept separate so that the theme can easily be changed without affecting the structure. For example, the styles should be defined in an external style sheet and not embedded in the HTML code of the pages. The structure of a website will be defined by a set of templates. It is good practise to make the templates modular rather than having page templates containing all the code for each page. This allows site-wide changes to be easily applied. For example, the footer may be mostly identical between pages.