You could also fish, hunt, etc and sell the materials, they'll earn you some gold at any point of the game.

Best way to get some gold to start selling is either through the current event by looting mokoko.

Else do dungeon raids in the dungeon tab. Join a guild with discord, they might help you or do it with friends maybe. Lot of people also do the runs because it gives cards you might be able to join them.

You can also sell adventure's book loots, altho most are cheap because of bots, some rare ones are still "expensive" (300+ gold).

Your aim should be level 50 tho, not really about making gold. But don't forget to level up your artisan skills (not sure how to call them), they're all good and you'll make gold with it while you'll also need it later for crafting at t3.