What do you need to develop your own themes and plugins? If you are new to HTML and CSS, you need
- Online HTML, CSS, JavaScript and PHP tutorials.
- A text editor. WordPad is good enough if you are on a windows computer.
- An image manipulation program like http://www.gimp.org/
- A file transfer program like http://filezilla-project.org/ to transfer your files to your web or production server.
Then query:
build your own wordpress themes
build your own wordpress plugin
Links:
http://codex.wordpress.org/Using_Themes
http://wordpress.org/tags/sub-theme
http://wordpress.org/support/topic/sub- ... -wordpress
Litterature: http://www.packtpub.com/books/wordpress
Don't forget web standards: http://www.w3.org/
Examples:
http://www.alistapart.com/articles/doctype/
http://www.w3.org/News/2011#entry-9116
http://www.alistapart.com/articles/fluid-images/
http://www.opera.com/company/education/curriculum/
http://www.schema.org/
http://www.webproworld.com/webmaster-fo ... schema.org
http://www.usability.gov/process.html