social practices

Hello!
	I am gearing up to write a large paper on social practices, and I am
interested in delving again into Foucault's writings on the subject.  My
question is this: Does anyone know if Foucault ever gives a general,
abstract account of what a practice is?  For the most part all I am finding
are passages that talk of "practices" (along with discourses) as a plural
noun, that do not suggest an established means of differentiating one kind
of practice from another, or of picking out what is and what is not a
practice.  
	There is, obviously, a great deal else of interest in Foucault on the
topic of practices...I just need to work out something to say on this
particular set of foundational theoretical issues (i.e. those revolving
around the matter of what a practice is), and I figured there were some key
bits in Foucault on this that I was missing.
	Thanks

Brandon Claycomb