How to Unlock Trick Shot Achievement / Trophy
Trick Shot – Defeat an enemy from long range with the sniper rifle in the story.
Where I got this achievement is shortly after a specific bell puzzle where you first pick up the Sniper Rifle. Once you step outside you’ll see plenty of flying enemies. There is a tower that a majority of them will be around (looked the furthest away from me to my right or NW from the window exit).
They will periodically perch like a gargoyle and I aimed down the sites, aimed for the upper body/head with the Sniper and took my shot. Achievement popped right after. If you don’t see one perched you can wait a fairly short period and one will land again.