When you understand how CGI receives information and how it sends it back to the browser, the actual quality of your final product depends on your general programming abilities.
Generality applies more to CGI programs than to other applications.
You will find as you start developing your own CGI programs that there are a few basic applications that you and everyone else want to do. For example, one of the most common and obvious tasks of a CGI program is to process a form and e-mail the results to a certain recipient. You might have several different forms you want processed, each with a different recipient. Instead of writing a CGI program for each different form, you can save time by writing a more general CGI program that works for all of the forms. However, in order to become an effective CGI developer, you need to have a deeper understanding of how the CGI communicates with the server and the browser.