We've all been on the site long enough to have figured this out.  So this is mostly for the newbies that will come.  As it was once said, "If you build it, they will come."  *snicker*

This is a great article on critiquing. 

How to Critique Fiction
http://www.crayne.com/howcrit.html

For our guidelines I'd like to keep it simple.  This still gets specific but it isn't overwhelming or line by line.  You are certainly more than welcome to do a line by line critique if you so choose to do so.  I know I probably will from time to time.  But just know it isn't expected of you or your fellow authors in this writing group.  This is all I expect everyone to cover.

A.     Let the author know if this is not your favorite type of story.
B.    Write down your impressions as a reader.
C.    Try to give feedback on what could be changed.
D.    Give examples of improvements, if possible.
E.    Praise where praise is due.
F.    Never criticize the author personally.
G.    Critique as you would want to be critiqued.