1. Selling on warriorforum - is not a real business model. Very low prices...
2. First learn basic HTML/XHTML and CSS. > W3Schools Online Web Tutorials Get to the level when you can write a html/css page from scretch...
3. For WP themes... always keep the Codex open in a window. Get familiar with it to know where to find relevant info. Download free themes from WP and analyze, study, dissect their template files.

When you understand how a WP theme works and you know very well XHTML/CSS (later HTML 5) then you can answer your own question - how long it takes to create one theme. I don't have the answer, although I make WP themes since 2005 (and use Wp since 2004). Some themes are simpler, other way more complicated, depending on the functionality and the underlying design.

If you want to sell themes here, I would suggest you not to learn WP. You won't get the returns you would expect. Here everyone looks for "cheap and best" which ironically can never go hand in hand.

You can learn about Wordpress web design at this popular Wordpress Learning Web Portal, How To Build A Wordpress Website - Your #1 Guide To Building Your Wordpress Website.

I saw a guy offering a basic video course that walks you through
the basics of Wordpress. It's in the WSO section if you look.

I wouldn't bother trying to sell your designs here though.

Steve

Best to look at some video tutorials about it. Just type in Google "PSD to HTML to WordPress" or whatever. Indeed there are many good tutorials on this subject on the internet. ..

start with a framework, "thesis" is the best, after what I have heard. Good luck =)

Link: http://diythemes.com/