I found these other great tips for making money
1. Best way to make money is doing speed runs, as you get further in the game and get better gear, just hunt large monsters whose parts you do not need and sell them straight from the reward box.
2. You can convert guild points to money through replication, you can speed run lower end monsters and sell their junk, or you can run through a mission with a frenzied creature and they may give you a frenzy crystal or 2 netting you 2k per crystal plus the reward.
kulekitsune answered:
3. In Dundorma- the city with the Assembly- There is a bridge over a small creek. On the left side, there is some rigging/netting that has a fishing spot over the side. You can catch fish called Coinperch here endlessly. the small sells for 250, the medium for 500 and the large for 2,500. They don't need special bait or anything, and you can also get Glutton Tuna and Gastronome Tuna that have a chance of giving you various random items when eaten on a quest. You can also catch Canthagea fish, which can be used for gratuities to make the farms produce more bugs, shrooms, plants and berries. Fighting monsters made me about 20,000 minus consumed items in about an hour and a half, fishing in Dundorma made me that much without consuming items in twenty minutes. It gets hella boring, though.
4. Just to add onto kulekitsune's answer, if you are going to do this method I suggest getting ranger as one of your armour skills means the fish will take the bait on the first attempt.
No idea what replication is though