Lively artist gets one planning (10)
I believe the answer is:
strategist
'one planning' is the definition.
The answer is a person as well as being a singular noun. This is suggested by the definition.
'lively artist gets' is the wordplay.
'lively' indicates anagramming the letters (I've seen this in other clues).
'artist'+'gets'='artistgets'
'artistgets' with letters rearranged gives 'STRATEGIST'.
Can you help me to learn more?
(Other definitions for strategist that I've seen before include "general" , "Long-term planner" , "Expert on the art of planning war" .)