Here's what I got on where to party and with how many ppl you should bring with you around the 'The Black Shroud' zone. I've only partied till rank 15 Marauder so I'm not so sure where to go after that :(. But anyways, here goes~
(Disciple rank - Location - Mob - Summary)
Rank 9 ~ 12 - North of Camp Emerald Moss - Wolves - A four-man party with a Conjurer should be able to kill these wolves. I was getting around 100~400 Axe exp from these guys.
Rank 12 ~ 15 - North of Camp Emerald Moss - Wolves - You can decide to just bring a Conjurer (or vise versa) with you and kill these guys. They should give good enough exp. Or you can....
Rank 12 ~ 17 (I'm guessing even a bit higher) - The Mun-Tuy Cellars (North east from Camp Emerald Moss) - Opo-opo - Have a five/six-man party, with a Conjurer of course, and go inside The Mun-Tuy Cellars and kill Opo-opos. Getting there is pretty easy. Once you reach a big room after the long creepy hallway, go north and you should eventually find the Opo-opos. Don't worry Puk's do not agro, just be careful from hitting them with AoE attacks/spells
Also note that because you get Disciple exp from hitting the monster, you get less Disciple exp if you kill the monster too fast. So remember not to get too many people to bring with you and at the same time, bring enough to take down the monsters.
If you know where to party after Rank17 or know a better place to party than what I mentioned, please share it with everyone, after all, FFXIV is a new game that does not have a lot of info about it. So please share you're info :)
* Edit: How to find Opo-opos at The Mun-Tuy Cellar
Edited, Sep 12th 2010 4:28am by Kakinashi