The most common and most likely answer to this crossword clue is the 3 plus 6 plus 5 letter word THE COMMON TOUCH
I've seen this crossword clue in The Times
T
H
E
C
O
M
M
O
N
T
O
U
C
H
More clues leading to the result THE COMMON TOUCH
Buddy explains!
The straight part
We know that "Ability to mix with ordinary folk?" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case ability to mix with ordinary folk? = the common touch.The cryptic/wordplay part
In cryptic crossword there's often an wordplay/cryptic part as well.This part involves a more complex hint, such as an anagram, homophone, hidden word, etc.
Sadly, We don't have an explanation for this specific crossword clue yet.