For the crystal prob you can ALWAYS get a new job and lvl up on bees and the sort for free crystals.

There are types of farming, i farm elementals where i just camp a spot where it spawns and beat every other competitor. Training mob farming includes getting a ton, then using a Weapon Skill or -aga spell that will wipe out all of them around you. Usually mob train farming should be done in an area where there isnt alot of parties you will endanger and/or steal their mobs.