Prepare for the best (5)
I believe the answer is:
prime
I believe this clue is a double definition.
'prepare' is the first definition.
(priming is a kind of preparing)
'the best' is the second definition.
(thesaurus)
'for' is the link.
(Other definitions for prime that I've seen before include "Two for one" , "Monastic service; best quality" , "Number with no factor but itself and 1" , "Main; make ready" , "Prepare to set off" .)