What's the difference between practical and literary criticism?

The post by sdeadder gives a good place to start further
research into what exactly Practical Criticism is.  I like to think of this approach to
reading and analyzing a text as a very formalist approach where I am focussing on the
words and then the sentences on the page.  I am primary looking for diction, imagary,
symbolism, sound devices, techniques of characterization, structure, narration style,
syntax and other specific literary techniques.  I am still looking to understand the
work as a whole, but I am focused on the words on the
page.

Literary criticism has lots of sub-headings.  When
you are engaged in literary criticism, you are looking at the words on the page (like
above), but you are also considering other lenses with which to look at the text.  As
noted in the other post, you may consider author's background or historical context.  It
is in this type of criticism that you start thinking about a feminist reading, a Marxist
reading, a psychoanalytical reading, a political reading, a moralistic reading etc. 
There are numerous approaches to reading a text that can provide new understanding to a
work.