It's kind of annoying to level DPS classes as you can't queue for dungeons while your chocobo is out. Best thing to do is just get in the dungeon queue, then do other stuff for the half an hour it takes to pop - you can switch classes and do gathering/crafting while you wait, just nothing that involves joining other groups or going into instanced stuff.

It's kind of sucky at low levels as not so many people are doing FATEs in those zones, but once you can get into the 30s, there are always loads of people farming in Coerthas, and you don't even need to party up, just follow the herd and tag as many mobs as you can.