Perfectly done imitation volume shows (8)
I believe the answer is:
copybook
'perfectly done' is the definition.
(copybook can mean optimal or perfect)
'imitation volume shows' is the wordplay.
'imitation' becomes 'copy' (I've seen this in another clue).
'volume shows' becomes 'book' (I can't explain this - if you can you should believe this answer much more).
'copy'+'book'='COPYBOOK'
(Other definitions for copybook that I've seen before include "Standard" , "Conventional - perfect" , "It's used by schoolchild" , "Exemplary" , "It contains models of writing for learners - don't blot it" .)