DISCLAIMER: Some people say they've been banned for using this, but there's no proof they've been banned from using Yeti Sonar, or even banned in the first place. As with any third party program; use it at your own risk.
This might seem like a no-brainer for some, but using Yeti Sonar lets you find the ephemeral crystals so much faster.
I ran around in Azsuna today and found the first crystal by the Daggerbeak world quest in the cave. I used all the macros on wowhead comment section, but couldn't really find any.
I downloaded the Yeti Sonar program quickly and tried using some of the model IDs. I won't recommend using the specific model IDs, since every crystal it's own unique ID, and there's like 40 possible crystal spawns so yeah.
Therefore you should just turn on Track Objects and open up the radar screen. Zoom out a bit and you should be able to see them really far away. I found two crystals at the murloc camp near the Azurewing Repose and I could see them on my radar even though I was inside the cave. Took me 1 hour running around without it and I found 3 crystals. Last two was within 10 secs of each other at a spot I had looked over 3 times.
TL;DR 1. Get Yeti Sonar. 2. Turn on Track Objects. 3. Open up radar, zoom out A LOT (in the radar just scroll down) and run around the whole map looking at the radar. Use the waypoint macros from wowhead if you want to make a route easier. 4. Loot all 5 crystals that's up and you get the mount in your bag. Don't die or you'll have to click the ones you already clicked again.
The intent of this post is for people who's seen the crystals up really, but user h42 figured a way to keep it running and it'll give you a sound if it scans it on the radar: