Friend with ideas about fence (8)
I believe the answer is:
palisade
'fence' is the definition.
(I know that fence can be written as palisade)
'friend with ideas about' is the wordplay.
'friend' becomes 'pal' (pal can mean a friend).
'with' means one lot of letters go next to another.
'about' indicates anagramming the letters.
'ideas' anagrammed gives 'isade'.
'pal'+'isade'='PALISADE'
(Other definitions for palisade that I've seen before include "paling" , "Stockade" , "Line of stakes as a defence" , "fencing" , "A side lap (anag)" .)