Used to lack experience, but following advice to young man? Capital! (6)
I believe the answer is:
warsaw
'capital' is the definition.
(capital of Poland)
'used to lack experience but following advice to young man?' is the wordplay.
I cannot really understand how this works, but
'man?' could be 'saw' and 'saw' is located in the answer.
The remaining letters 'war' is a valid word which might be clued in a way I don't understand.
This explanation may well be incorrect...
(Other definitions for warsaw that I've seen before include "Polish capital" , "Largest city in Poland" , "Capital city on the Vistula" , "Polands capital" , "1929 international agreement regulating commercial air transport" .)