Proceeding with difficulty, Heather takes in mischief-maker (7)
I believe the answer is:
limping
'proceeding with difficulty' is the definition.
'limping' can be an answer for 'proceeding' (limping is a kind of proceeding). I'm unsure of the 'with difficulty' bit.
'heather takes in mischief-maker' is the wordplay.
'heather' becomes 'ling' (synonyms).
'takes in' is an insertion indicator.
'mischief maker' becomes 'imp' (I've seen this in other clues).
'ling' placed around 'imp' is 'LIMPING'.
Can you help me to learn more?
(Other definitions for limping that I've seen before include "Walking with difficulty" , "Hobbling" , "has evidently been kneecapped?" .)