Line in red and white stripes originally without success (7)

'without success' is the definition.
('success' can be 'win' (I've seen this in another clue) so maybe 'without success' can be ''winless')

'line in red and white stripes originally' is the wordplay.
'line' becomes 'l' (used when specifying particular lines from a poem).
'in' is an insertion indicator.
'red and white' becomes 'wines' (I can't justify this - if you can you should believe this answer much more).
'originally' suggests taking the first letters.
The initial letter of 'stripes' is 's'.
'l' going into 'wines' is 'winles'.
'winles'+'s'='WINLESS'

Can you help me to learn more?