There are many things a developer can do to enhance a web page. In my research, I found 2 very interesting tutorials. The first one covers CSS, and how it can be used to make a web page much more visibly appealing. The second tutorial covers JavaScript, and how it can be used to make a web page feel alive.
This tutorial from Mozilla gives a nice lesson on CSS for beginners. It also explains various things that can be done with CSS, in order to make a web page look as good as it can.
URL: developer.mozilla.org
This tutorial, also from Mozilla, covers the basics of JavaScript and how it can be used to make a web page feel like something more than words on a screen. It covers how JavaScript is used to make pages responsive and interactive, thus giving web sites much more depth.
URL: developer.mozilla.org