A Lot of Great Shots!

I've found that on the balloon ride in Thaldraszus you can collect many "great shots" with the Marmoni who almost always make some "special" move (moving their arms).

Also, if you're in a raid it doesn't count towards the quest and you can take as many shots as you want.

Trying to get this as the expansion winds down.
First, you need to unlock Cataloging World Quests, see this page or Sipder's comment.

I didn't bother reading any of the introductory quest text so I had no idea how to get "Great" shots.

During world quests, you board a vehicle and will see various wildlife on a pre-planned route.
You're supposed to Catalog (Default button 1), whilst aiming the camera at wildlife.
You receive "Great" shots by cataloging wildlife when they perform some form of emote.

Some emotes I've seen and received achievement progress:
Dolphins jumping out the water
Ducks standing and flapping their wings
Salamanthers roaring
Thunder lizards stamping

Sometimes I've received double credit and I'm not sure why.
Once you've taken a photo of an NPC Wildlife, you cannot restart the World Quest and photograph that NPC in that specific location again, to repeatedly receive achievement credit.