Most effective money making strategies

I've found using lots of Food Rations and the "Turbo" key with a gamepad to be the most effective way to rack up experience and Golz, but you need to make sure you are leveled enough to not get wiped out if you aren't paying close attention.

To save on burning Golz on lots of restoring items you can also pick up a bunch of Water Rations in addition or instead of the Food Rations and then just use magic to heal your team in between fights and by winning fights allow the Water Rations to restore some MP, but make sure you don't completely deplete your MP on healing, as sometimes you might need to use it to end a fight quickly if your guys are getting their butts kicked. This is why I tend to let the Food Rations do the majority of the healing (they are also cheaper) and just top up via magic any time I see a "Save" sign just to make sure the guys are ready to win.

Grinding gets a little easier once you are almost to Death Mountain and can hunt down the "Hunter Technique" for Johnny that increases the random encounter rate, don't forget to equip it when grinding, but unequip when going into a new area because if the monsters are tough, you'll burn through your restorative items/MP way faster.

(Much) later in the game you can equip both "Hunter Technique" and "Warrior Technique" for an almost ridiculous encounter rate that will net you lots of Golz and EXP, but again it is a balance between how much you have to pay attention to not die and how much money you get. There is a magic oasis that has a screen that will loop you back to the other side of the map when you leave via any side, this might be the best place to tape your joystick in one direction and sit something on the Turbo button and let it ride (again assuming your guys won't die resulting in a Game Over).

My experience has been to go back one or two areas after completing the story in one area and grinding for a little while until I can easily use Turbo, at that point I get a little bored and continue the story, but that grinding usually gets me enough Golz for all the skills I need.

Another thing to note is that you don't typically need to collect all the weapons/armor in every town along the way, it makes a few fights easier, but if you are grinding at all you should be able to survive most fights and skip over one or two "levels" of equipment and save quite a bit of Golz, put it into your Powers for maximum effect. Another way to do this is to only upgrade half your characters in each town, eg fighters get weapons and mage/healer get armor to boost their MP, then in the next town grab the better armor for the fighters and a nice SPI boost for the mage/healer.