Look quickly in small tin (4)
I believe the answer is:
scan
'look quickly' is the definition.
'scan' can be an answer for 'look' (I've seen this before). I am not certain of the 'quickly' bit.
'small tin' is the wordplay.
'small' becomes 's' (abbreviation - e.g. clothes size).
'tin' becomes 'can' (synonyms).
's'+'can'='SCAN'
'in' acts as a link.
Can you help me to learn more?
(Other definitions for scan that I've seen before include "make a detailed copy of" , "Look over cursorily" , "Read superficially" , "Examine (to transmit)" , "short survey" .)