Again, go over adult's tips on two school subjects (6)
I believe the answer is:
repeat
'again go over' is the definition.
'on two school subjects' is the wordplay.
'on' becomes 're' ('on' can be mean 'with reference to').
'two school subjects' becomes 'peat' (I am not sure about this - if you are sure you should believe this answer much more).
're'+'peat'='REPEAT'
'adult's tips' acts as a link.
I am not very happy about this link. Some or all of it may be part of another bit of the clue.
Can you help me to learn more?
(Other definitions for repeat that I've seen before include "Say, do or occur again" , "Parrot" , "Another chance to see show" , "Reiterate" , "Further airing" .)