In school, is tending to pay attention (6)
I believe the answer is:
listen
'pay attention' is the definition.
(I've seen this before)
'in school is tending' is the wordplay.
'in' says the answer is hidden in the clue.
'LISTEN' is hidden in the letters of 'school is tending'.
'to' is the link.
(Other definitions for listen that I've seen before include "Be silent in order to hear" , "Make an effort to hear" , "what buggers do" , "Give one's attention" , "Try to hear (something)" .)