Check the
Beastmaster Forums for general soloing, if you're just asking how to level a job to 75 by yourself.
Aside from that, FFXI isn't a solo exp game, sure some jobs can solo from time to time. Most jobs can go from 1-15 fairly quickly (though most stop at 10 and head for the dunes to pt). Puppetmasters and Dragoons are pretty effiecent soloers and can exp while LFG. 51+ Blms can manaburn solo for some easy exp every now and again.
Rdm/nin of course. Thf and Nin can solo alot of things really well. Most jobs /whm or /nin can solo some exp if you're party disbands at 500tnl.
As for areas, just go to where you exp'd with as a party 10-20 levels ago. Most people exp on certain monsters because they're generally safer to fight, and have camps where's there is little or no chance of aggro or links.
Again, this game doesn't have much in the way for soloing exp. Some missions can be soloed and quests. You solo when you farm. But SE really emphasized the "group activity" thing. And really, when you think of it, how many Final Fantasy's did you only have a single person party the entire playthrough?