I posted in this thread a couple days ago about having finally completed the Skyshard grind back in April, similar to you I already had 4 Skyshards sitting in the bank from a couple years ago! Thanks to Rarity I have screenshots of getting each of the 6 Skyshards I needed so I know how many attempts it took to get each one and where I got them, so I hope this proves of help to you:
Skyshard #5 took 1109 attempts, Ancient Mogu Spirit @ Tu Shen Burial Ground
Skyshard #6 took 99 attempts, Shao-Tien Sorcerer @ near the cave above Gao-Lai Halls
Skyshard #7 took 466 attempts, Ancient Mogu Spirit @ Tu Shen Burial Ground
Skyshard #8 took 4108 attempts, Ancient Mogu Spirit @ Tu Shen Burial Ground
Skyshard #9 took 364 attempts, Ancient Mogu Spirit @ Tu Shen Burial Ground
Skyshard #10 took 904 attempts, Ancient Mogu Spirit @ Tu Shen Burial Ground
Total of 7050 attempts spread over several days using 4 toons, each on a different server, I always started at around 2-3am to reduce competition. Even so, I found the areas around Gao-Lao Halls, Ruins of Gao-Lai and Winterbough Glade were constantly being farmed by at least one other player, so I focused on the Tu Shen Burial Ground area and rarely had any competiton. One other suggestion is that once you have your 10 Skyshards go looking for Alani
before you combine them into a Sky Crystal, especially if you have alts on other servers! If Alani isn't up on one server you may be able to find her on another server, then you can mail your 10 Skyshards across, but the Sky Crystal is BoP so you can't mail that! That was the mistake I made, combined my 10 Skyshards into a Sky Crystal and then went looking for Alani, only to find she wasn't anywhere to be found! Fortunately I as only about 20 minutes away from server restarts, after which I found Alani straight away, so only had to wait about 30 minutes to finally add the Thundering Ruby Cloud Serpent to my collection!