I'd like a free premium membership I suppose.
Due to my intense hate for Valkurm Dunes, I solo all jobs to ~20. As I'm sure everyone knows, Ghelsba is a pretty nice place ~7-20 to solo--or at least its my area of choice. I hate La Theine and its overcrowdedness and sparse mobs that actually con what you're looking for.
Anyway, enough of my blabbing. Here's what's up. Level ~13-20 fight Orcish Grunts, Stonechuckers, and Neckchoppers in Ghelsba Outpost and Fort Ghelsba. For lower levels, you want to be in area around the river in Ghelsba Outpost. When things get slow down there, move to Fort Ghelsba and go up the elevator.
Now that's nothing spectacular, I know. However, for most jobs, I sub Bard. Most people fail to see the usefulness in this. And I fail to understand their incompetence. Keep Paeon up at all times, and you never have to rest as most jobs, and even if you do, what's a minute's rest with your low max HP at those levels going to make a difference?
In order to continue to do this to 75 as I have done several times now, you'll either need a good friend or a 2nd account. I have both. I prefer that my friend or 2nd account have lv 16 Monk, as it seems to be the ideal level, and Monk is simply the best DD at the time. Not only that, but Monk is exceedingly simple, meaning its easy to have a bot/macro run it for you. Which is what I do.
Any looping extended macro program will work. I use Apnea's MacroMaster myself. I put the Sync-Whore on follow on my character, and set a loop for a macro as such:
/attack <t>
/wait 1
/ja "Boost" <me>
/wait 1
/ws "Combo" <t>
/wait 1
Other than Combo failing due to distance, its pretty perfect. Oh and the automated idiot gets stuck on stuff sometimes. Of course you just open the window for a moment and move and put follow back on. I usually set myself to Quartermaster as well, so the sync-whore never has to leave the area.
If you notice you're running low on HP and Sync-whore isn't, you can just engage stuff but don't get close enough to hit it, and the sync-whore will go solo it. By the time your HPs are equal, Paeon should've done well enough you feel safe to keep going.
Eventually the sync-whore is going to level. So... Kill it a few times. Now you might think this takes a while, but not at all. Have your character switch to something with Raise, and have the "over-leveled" whore die -> raise -> die -> raise. You get it. It only takes a few minutes to warp to San d'Oria, (of course your home point is going to be there, there's no point in exping anywhere else

) Change to something with Raise, exchange conquest points for another warp, and walk there. Besides, its nice to go sell some stuff and clear your inventory occasionally anyway. And its not like you actually have to do this every time the whore levels either. I'd de-level him to lv 14 out of convenience and probably not do it again until about lv 18. This was extremely easy as Paladin, since I just took level sync off and I had Raise.
When I actually level a job through these levels, I get 20k/hr average. With level-sync duo, I still get 15k/hr average. My friend and I reserve our Monks at low levels just for each other to use.
I've never read or heard of this type of thing posted anywhere else, so I thought it was worth a shot. Hopefully this doesn't come bite me in the !@#$%^&* when everyone comes to Ghelsba and/or SE messes with level-sync. I suppose this would work in the other 2 populated beastman areas; Giddeus and Palborough Mines as well, however I've always prefered the easily-navigable Ghelsba. Of course due to the many scrolls of instant-warp needed, it might be easier to use the other 2 if your home nation is of its close proximity.
I've done the math by the way; its 845350 exp 1-75. Its 820400 exp from lv 14-75. Getting 15k/hr on average, only leveling for 2 hours a day and you'd be 75 in a month. Playing my regular 10 hours a day and I got 75 in a week, even with taking a few trips back and forth to get raise to delevel the sync-whore. Obviously its ideal to use a DD job and sub Bard as I have said, but as far as I can see, this will work just as well with any job. Your max MP can't be that high that it makes a huge impact on exp when you rest at this low levels if you decide to level a mage this way.
Of course it has its downfalls, Although large amounts of fire crystals and random items do add up, I'm not sure if it makes up for things you'd get in a party. However, you are reaping all of the goods for yourself, so I'm not sure. Not that it really matters much, once you get a job to 75, you're better off with gil than you were before.
Also, you'll be able to keep the same equip all the way, so that's about as cheap and convenient as it gets. I've even got my friend's monk Tropical Punches +1, just because I'm so devoted to this method haha.
I hope my guide does you well, and doesn't harvest a ridiculous amount of noobs that don't know how to play their level 75 job. I think I can validly use this method, as I've been playing the game for 5 years.
*I can confirm that DRG x2 I get a straight 20k/hr without exp rings at most levels from 14-20
*I found an easier way to level down. Set your HP at an outpost and just continuously Home Point. Its nice to have Outpost Warp there, and make sure its no somewhere you can't get out of, because remember, you'll be a lower level!