Again, each one of the society has to keep in mind (8)
I believe the answer is:
remember
'to keep in mind' is the definition.
(I've seen this before)
'again each one of' is the wordplay.
'again' becomes 're' (prefix meaning 'again').
'each one of' becomes 'member' (I can't explain this - if you can you should believe this answer much more).
're'+'member'='REMEMBER'
'the society has' acts as a link.
This may not be correct. Some or all of it may belong to another bit of the clue.
Can you help me to learn more?
(Other definitions for remember that I've seen before include "Think back" , "Call to mind" , "Bear in mind" , "Mark" , "Commemorate" .)