Some tips that worked out for me

I did all the Start Quests in my home town, but when I got to the new cities and close areas I did not do any of the lv1-15 tasks - I saved them for my second (and third) classes (u can level up very quickly to mid teens without effort)

Dungeons. Run them again and again again (good xp low-mid levels)

Craft/Gather. If u keep your craft near your Main, u can stop taking the goods as reward in quests and take the money. From level 15+ I took money 99% of time - always the money!

Market Board. If you're lucky some fool has listed something for 9 gil, instead of 250-500 gil

FC/LS. I trade a lot with my FC/friends; goods for services etc. Between us all we have nearly everything, e.g. swap 99 Mahogany logs for a lv44 Botanist axe from my blacksmith friend, or countelss leathers with my goldsmith friend for crafting jewelry.

This game is the best fun I have had for a long time! Glad you are enjoying it!
Have fun!! Always have fun!!