So I want to start designing

[Gaijin]

Thanks for the inputs guys.
@ Gaijin, I've seen the w3school is crap.

Also if I learn html,css and php would that also give me knowledge on SEO?

I don't see w3school as crap, it has enough information to serve you as a door into the world of web development.
It doesn't take you long to understand the languages that were mentioned, and w3schools is good for explaining you the structure of each language. Once you understand the languages, it is up to you to learn them.

You need to write a lot of your own stuff, make a lot mistakes and learn from them, there are more good sites that can teach you HTML and other languages, w3schools has all information so you don't have to search around.
Once you are able to write your own page, you simply start looking at some other codes and try to understand them.

You can view the HTML structure of any page you visit, you can look for specific tutorials and learn from their techniques or just code something on your own, that is the best way to improve your understanding of all thos languages and eventually mix them later.

SEO is a term describing a group of techniques which are being applied to the coding style, advertising, site-content... etc...
You will not learn any seo techniques by learning HTML/CSS/JS or PHP.
The above languages can help you to understand how search-engines find and parse your site, and you can find the correct technique to improve your site's results for the search engine.

This topic comes at last, you don't have to worry about it know, once you get on with php you can start looking at seo too.

http://net.tutsplus.com/category/tutoria...echniques/
http://net.tutsplus.com/category/tutoria...ript-ajax/
http://net.tutsplus.com/category/tutorials/php/