It is an honor and an important responsibility to write a letter of
recommendation.  To help me do my best, I would appreciate the
following things from you:

 - enough warning so I can get the job done.
 - specific instructions on what you need me to do with the letter
   when it's ready.
 - your CV so I can browse to get a broad picture of what you do.
 - a list of information about our *direct* connections (what
   date/situation did we meet? what have we done together?).
 - what you are applying for
 - a brief description of what perspective I am bringing to the table
   (what should I be commenting on that your other letter writers
   might not know as well as me?)

Thank you!