When you first start a character in FFXI you get to pick from 6 basic jobs. These jobs align with the characters from the original Final Fantasy with a couple name changes: Warrior, Monk, Thief, White Mage, Black Mage, Red Mage. You can switch between them whenever you want but you're stuck with those 6 jobs until you reach level 30 on one of them. At that point you can start doing quests to unlock the other 14 jobs in the game. I'm approaching level 30 and I figured I should take a look at what those quests entail to see if I could be working on gathering items or reputation needed to do those quests. There are a couple jobs I particularly want to unlock (Corsair, Beastmaster, Ninja, Ranger) but I probably will do the quests to unlock all of them at some point. So, what do we have to do?
Paladin - Do a series of 3 quests from a guy in San d'Oria. Get a revival tree root from King Ranperre's Tomb, get stalactite dew from Ordelle's Caves, get a knight's soul from Davoi. The first two are low level quests so I could get those done now if I wanted. The last one is in a level 75 zone so you need to be sneaky to get in. My highest job is White Mage and I'm actively trying to farm up the invisibility spell so this seems like it should be fairly easy for me to pull off.
Dark Knight - Get a quest in Bastok to travel to Palborough Mines and take a boat ride. Find chaosbringer, a truly abysmal sword. Get the killing blow with a normal weapon swing with the terrible sword on 100 enemies of any difficulty.
Beastmaster - Get your chocobo license. Pick a flower that grows at night in Qufim for the chocobo guy in Jeuno.
Bard - Quest chain in Jeuno. Trade a parchment to a rune in Buburimu Peninsula. Then go to Valkurm and click on a rune.
Ranger - Quest in Windurst to watch a tiger die in Sauromugue Champaign.
Samurai - Quest in Norg, so you need a Kazham airship pass which you get by obtaining coffer keys from beastmen cities near San d'Oria, Bastok, and Windurst. Need a hatchet and to kill two level 33ish NMs.
Ninja - Quest in Bastok that eventually takes you to Norg so you need the same airship pass. Must also kill a group of 3 level 32ish NMs. In order to be at all useful as a ninja though you need to learn the spell Utsusemi (Edge's spell from FFIV that puts up shadows making him invincible) and to learn that you need reputation with the Tenshendo. You get that by farming a ton of Yagudo bead necklaces around Windurst or tine ore around Bastok.
Dragoon - Quest in San d'Oria. Needs a hatchet and to travel all around the world. And then you have to kill a level 40 NM in an instance which only allows people on the quest or who have completed the quest to enter which means it's harder to get help than for the other ones. Sad, since dragoons look cool.
Summoner - Farm up a rare/exclusive item that's a very rare drop from any leech type mobs. Have it in your inventory and get a quest in Windurst to see all the weather effects. Travel the world finding weather.
Blue Mage - Quest in Aht Urhgan Whitegate. To get there requires being a member of the Tenshodo which requires either buying an item for 10k or getting reputation with them. (These are the same people who give you the quest for the ninja spell Utsusemi.) You do get the 10k item back either way, so you can either get there for minimal cost or by making 10k in the process if you have the rep. The quest itself involves answering some questions, trading a quest item from another zone (one of 3 so you could prepare in advance by having all 3 with you I guess) and then doing some other traveling stuff.
Corsair - Quest in Aht Urhgan Whitegate, same as Blue Mage. You need to farm a key off of level 80 monsters or pick a lock with a thief or maybe sneak around and grab a key from a hard to reach place. Then sneak around a bunch of places filled with high level monsters to get a quest item.
Puppetmaster - Quest starts in Bastok but leads to Aht Urhgan Whitegate, same as Blue Mage and Corsair. Quest just involves sneaking around high level monsters to get a quest item. Similar to Corsair but without needing a key.
Dancer - Quest starts in Jeuno and ends up taking you through a cavernous maw thing to the past. There's a warning in the quest description about taking care to use the right maws to get around the first time you go to the past. I don't really know what they're talking about at this point but the quest itself seems straightforward. Go get an item.
Scholar - Quest actually starts in the past, so I guess figuring out how that works is important for getting this job. Just requires trading 12 vellum to the quest giver and then using a mage job 2-hour ability. You can bring the vellum yourself or trade 12 rolanberries to a different NPC in the past to get a vellum, so 144 rolanberries total.
So, what can I do before I hit 30 to help out? Well, one thing I can do is read about the past to figure out what's going on for the last two jobs. I can get Tenshodo rep so I can travel to Aht Urhgan. (I need that rep for Ninja, Blue Mage, and Corsair all of which seem pretty sweet.) I could farm leeches to try to get the summoner item. I could get my Kazham airship pass. (Tom and I actually farmed up 1 of the 3 keys already.) I could do part of the paladin quest chain. I also need to get the invisible spell since a lot of these quests involve a lot of sneaking around.
I can actually do most of those things in the same place: Giddeus. A mob there drops Invisible. Most of the mobs there drop Yagudo Bead Necklaces. One of the 3 Kazham airship keys drops there. It may be a little too high level to solo at my current level but a couple more and I should be ok. I can also level lower level jobs (I need to level my Black Mage higher so it can be a proper sub job for White Mage) on easier Yagudo mobs for more necklaces.