Skill shown when skill is added to effort (8)
I believe the answer is:
artistry
'skill' is the definition.
(I've seen this before)
'skill is added to effort' is the wordplay.
'skill' becomes 'art' (both can mean a talent).
'added to' is a charade indicator (letters next to each other).
'effort' becomes 'try' (synonyms).
'art'+'is'+'try'='ARTISTRY'
'shown when' acts as a link.
This may not be right. Some or all of it may belong to another bit of the clue.
Can you help me to learn more?
(Other definitions for artistry that I've seen before include "Genius" , "Virtuosity - craftsmanship" , "great skill" , "Expertise" , "The skill to create works of art" .)