Lager drunk out of a can, with telling effect (8)
I believe the answer is:
relating
'telling effect' is the definition.
'relating' can be an answer for 'telling' (relating is a kind of telling). I am unsure of the 'effect' bit.
'lager drunk out of a can' is the wordplay.
'drunk' indicates anagramming the letters.
'out of' is an insertion indicator.
'a can' becomes 'tin' (synonyms).
'lager' is an anagram of 'relag'.
'relag' going around 'tin' is 'RELATING'.
'with' is the link.
Can you help me to learn more?
(Other definitions for relating that I've seen before include "Telling, narrating" , "Connecting things in thought or meaning" , "Narrating, recounting" , "Rendering" , "account" .)