Learn Code

In order to have complete control over your web content, you'll need to master the various languages used to make web pages.

HTML (HyperText Markup Language)
This is the most common language on the web. The easiest way to learn is through trial and error, and by looking at the code behind existing web pages. Go to VIEW SOURCE in your web browser to see the code for the page you are currently looking at. The following sites are good places to start with HTML:
Dave Raggett's intro HTML: http://www.w3.org/MarkUp/Guide/
Dave Raggett's advanced HTML: http://www.w3.org/MarkUp/Guide/Advanced.html
HTML Goodies Primer: http://www.htmlgoodies.com/primers/html/
W3 Schools HTML: http://www.w3schools.com/html/
CSS (Cascading Style Sheet)
CSS compliments HTML by allowing flexibility in style decisions, such as color, font size, positioning and more. Knowing this is just as important as HTML:
Dave Raggett's intro CSS: http://www.w3.org/MarkUp/Guide/Style
W3 Schools CSS: http://www.w3schools.com/css/
Javascript
Java
PHP & MySQL
Other