Inclines to get school markings (6)
I believe the answer is:
grades
'inclines' is the definition.
(I've seen this in another clue)
'school markings' is the wordplay.
'school' becomes 'grade school' (grade school is a kind of school).
'markings' becomes 's' (I can't explain this - if you can you should believe this answer much more).
'grade'+'s'='GRADES'
'to get' acts as a link.
Can you help me to learn more?
(Other definitions for grades that I've seen before include "Levels of proficiency or value" , "Assigns rank to" , "Numbers or letters indicating quality" , "Standards of performance awarded to students" , "Stages or degrees" .)