You can farm in stronghold, since those are the mobs around your level, to get all the tempest coins you can. If you are getting much, buy tempest shoulders and chaos them with the chaos scrolls from board game event, if you get 8 atk, you can get 200m/+ if you get more atk/matk AND % stat it's worth a lot, i just don't know how much.
Monster Park to get free Chaos Scrolls and Tempest coins (scroll them and hope for 7Atk+. I sold a 9Attack for 1.2b).
Sell leech, if you have a decent range, at LHC.
Kill Horntail for HTPs and CZak for Helms (only if you have Nx)
Farm LHC drops (while you sell leech). These go for 100-200k a piece.
All I can think about for now. You can also use professions to your advantage.