Improve on the ebbing tide (4)
I believe the answer is:
edit
'improve' is the definition.
(thesaurus)
'the ebbing tide' is the wordplay.
'the ebbing' says the letters should be written backwards (to ebb can mean to go backwards).
'tide' back-to-front is 'EDIT'.
'on' is the link.
(Other definitions for edit that I've seen before include "Revise - expurgate" , "Prepare to publish" , "modify text" , "Prepare (material) for publishing" , "Amend and correct" .)