Flag new introduction to novel containing nothing by writer (6)
I believe the answer is:
pennon
'flag new' is the definition.
'pennon' can be an answer for 'flag' (I've seen this before). I am not sure about the 'new' bit.
'introduction to novel containing nothing by writer' is the wordplay.
'introduction to' suggests taking the first letters.
'containing nothing' becomes 'on' (I can't explain this - if you can you should give a lot more credence to this answer).
'by' says to put letters next to each other.
'writer' becomes 'pen' (something which writes).
The initial letter of 'novel' is 'n'.
'n'+'on'='non'
'non' after 'pen' is 'PENNON'.
Can you help me to learn more?
(Other definitions for pennon that I've seen before include "Long narrow triangular flag" , "one might be all of a flutter" , "Narrow, swallow-tailed standard" , "Small triangular flag" , "Knight's personal flag" .)