The trick to succeeding in this game has two ways:
1.- getting a 75/37 character and killing high level goblins or farming some nice stuff to buy things for synthetizing or equipment and spells for lower lvl jobs, or simply spend hours fishing
2.- this way is tedious but in the long run its faster and safer:
start specializing on various crafting skills, go search the materials, like bone chips with jobs that will have con mobs regarding the items you need to synthetize. this way you will get crystals, materials and exp...
when you are too high to gain exp, switch jobs and continue getting crystals materials and exp...
when all your jobs are high enough to be gaining exp... just change areas or monsters, and continue leveling up other craft skills...
this method is slow but a constant gain... you will never lack money to have most up to date equipment, spells and food for ALL your jobs.
this is how you play this game.