Ask HN: how to learn principles of DB schema design?

I've been working with MySQL for several years, and I'd call myself pretty competent (I grok and use temporary tables, sub-selects, multiple types of joins, explain, etc.), but my knowledge of the * principles * of database design might be lacking. What I know basically comes from reading Wikipedia articles.

Aside from reading up on database normalization ( http://en.wikipedia.org/wiki/Database_normalization ), and related database articles, what do folks recommend ?

Just to be clear: if we were talking about programming languages, I'm not asking how to be a better BASIC programmer - I'm asking 'what is lisp and how do I learn it?'.

thanks,

TJIC