Help me tidy up part of church (6)
I believe the answer is:
temple
'church' is the definition.
(I've seen this before)
'help me tidy up part' is the wordplay.
'part' says the answer is hidden in the clue.
'up' is a reversal indicator (in down clue: letters go upwards).
'elpmet' can be found hidden inside 'help me tidy'.
'elpmet' backwards is 'TEMPLE'.
'of' acts as a link.
(Other definitions for temple that I've seen before include "One of two archbishops" , "centre of interest?" , "Shrine" , "'Shirley ..., child movie star (6)'" , "Side of head or holy building" .)