Long for start of concert followed by wild party (5)
I believe the answer is:
crave
'long for' is the definition.
(I've seen this before)
'start of concert followed by wild party' is the wordplay.
'start of' suggests taking the first letters.
'followed by' means one lot of letters go next to another.
'wild party' becomes 'rave' (a dance party).
The first letter of 'concert' is 'c'.
'c'+'rave'='CRAVE'
(Other definitions for crave that I've seen before include "Have strong urge" , "Beseech" , "Pine" , "Yearn for (something)" , "Powerfully desire" .)