[Ayrlie]

Before you head out there:
1. Signet/Sanction. Get this at every opportunity. Consider buying a signet staff if you need to. Rank affects duration of signet, along with conquest standings.
2. Basic Meds. When soloing you might want to consider regen drinks, potions, antidotes, echo drops, and muslums. While in a party you might want to consider antidotes, echo drops, and refresh drinks (for mages). Most of this can be purchased from NPC vendor.
3. Stealth Meds. Silent oils and prism powders, or shinoboi-tabi for Tonko. These are not cheap. Shinoboi-tabi can be made with clothcraft, the oils/powders with alchemy. The materials needed are relatively easy to farm, if you need to cut costs. You'll either find zones where mobs either aggro to magic and/or Sneak/Invisible is not possible.
4. Search zones ahead of time. /sea zonename is the best indicator. Some things to keep in mind is # of parties, or # of peeps soloing there. If you think the zone is packed, find another zone.
5. Certain mobs only work for certain types of parties. I.E. Amorphs/Elementals in general work well only for manaburn parties (most resist physical attacks).
6. Some zones work best for stationary parties, others for moving.
7. Gear. Most important part. Get gear that is proper for the job, the high-priced gear may not be the best gear.
8. Food. Varies on mob and what you're doing. Certain mobs require cheapest food possible.

http://www.kharvey.com/ffxi/xp/ is the guide. Version 2.1 is being uploaded right now. ToAU zone camps are starting to come in but its still incomplete. There is another post already stickied mentioning this page, but I put it here as well to help.