Generally you will see only get tutorials to design and code separately but recently There was this AWESOME tutorial going on a blog for 14 days that covered everything.
Let me look up my bookmarks and I'll link you to some good tutorials.
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Here it is:
How To Create a WordPress Theme: The Ultimate WordPress Theme*Tutorial
Some more links:
Photoshop tutorial to design a clean business layout | Grafpedia
How to Create a Blog Design from Scratch? | Blog design Blog for Blog Designers
Are you looking out for WP themes or just general websites?