The guy above as pretty much covered this subject but it is also a very good idea to put what is called the matrix numbers and letters on the sale as this could seriously affect the price you get for your album

these letters and numbesr are found in the run of at the end of the vinyl playing surface.

It will look something like K50048 LP  A1  or A2

Also it is a very good idea to state if the record is in the STEREO or MONO format as this again can add to the value of the album you are selling.