As well as tucking into Guinness, maybe distinguish oneself (5,3)
I believe the answer is:
stand out
'distinguish oneself' is the definition.
(I've seen this before)
'as well as tucking into guinness' is the wordplay.
'as well as' becomes 'and' (I've seen this in another clue).
'tucking into' indicates putting letters inside.
'guinness' becomes 'stout' (I am not sure about this - if you are sure you should believe this answer much more).
'and' put into 'stout' is 'STAND OUT'.
'maybe' acts as a link.
Can you help me to learn more?
(Other definitions for stand out that I've seen before include "Protrude" , "Catch the eye" , "Refuse to agree - project" , "Be highly noticeable" , "Be conspicuous, or persist in demands" .)