In world one, get yourself a ninja and some techs/scrolls (throwable items in shops, or enemy treasures). Use a black mage to cast a weak spell on those grey skulleater squirrels in Jacole Cave, then toss the tech on them8)

In the second world, get a ton of softs, or level5 doom and head down to the basement of Val/Bal Castle to level up your jobskillz. Lots of AP

Switch out job classes often-- don't just use the same ones over and over.