How to Become a Professional Web Designer and Programmer

Get a good vector graphics editor such as Adobe Illustrator. Making images using vector graphics is the easiest way to grasp graphics design, so spending some money on something like Illustrator or Fireworks will be a great help. Inkscape is a nice free and open-source alternative for beginners.

Look at how other web designers create sites, note how a menu or content area is laid out and then use that knowledge in your designs.
You will need to learn skills in XHTML(Extensible Hypertext Markup Language) and CSS(Cascading Stylesheets) as a foundation on which to build. Basically all websites are written in a combination of these two languages. A good place to begin learning them is at W3Schools. Good books on the subject are also helpful.

So far these two languages, XHTML and CSS, control only the look of the website. Neither of them cover any kind of programming aspects. A good introduction to actually programming websites (and indeed programming in general) is Javascript. Javascript takes care of all the client-side (scripts that are downloaded with the page and run on your local computer) programming. It will also teach you the fundamental concepts that will prove invaluable when you go on to learn server-side scripting using PHP.

Create dynamic websites using PHP and MySQL. These technologies will enable you to create a website that does not require you to make individual HTML pages but allow you to use templates to display multiple pages within the same design.

Create a web site that uses AJAX so you can utilise the server-side power of PHP without having to refresh the page thus saving bandwidth and enabling you to create 'interactive' web applications.
Install a web server on your Computer so that you can work on scripts locally without an internet connection. If you choose the PHP route try http://www.wampserver.com/en/. If you use ASP.NET use IIS available on most versions of windows.
Get yourself some script examples to "tinker" with: Finding a script to dissect is the best way to learn. Try CMS's like Drupal and Joomla
Install apache or XAMPP to test your scripts on your computer!
Start some Projects: Now with everything you know get yourself some hosting and a domain; then start creating sites.