Everything I know about creating and modding WordPress Themes are self taught. I have zero formal training in anything that has to do with html, css or php. It was just pure interest, passion and hundreds of trial and errors that enabled me to come up with reasonably good looking mods. Along the way, I just sort of picked up the knowledge needed and kept to that without going in depth to understand further than that. . Whenever I am stuck, there is always good old Google to turn to.
There are many sites where generous people will teach you about creating WordPress Themes for free. Some even take you by the hand in a step by step fashion. All you need is the patience to go through everything and that is something I sorely lacked. I wanted a fast track method, so I skipped most parts and read only the portion that teaches what I wanted to do at that particular time. Eventually, I turn into a mutant. Half noob and half geek, not knowing what to call myself. I am geek enough to mod an entire theme into something totally different, but when it comes to really creating a Theme from scratch, I am a big big noob.
I think it’s time to put all the bits and pieces of knowledge that I have gathered in order. A very good place to start learning how to create a WordPress Theme from scratch presently will be the tutorials from Themeshaper.com, How To Create A WordPress Theme. Highly recommended for people who are interested.