Long run - dragons, patron, and farming (buy credits with flux and patron with credits) - Short run market investment (or even trading if you know what you are doing), buy when supply is high and/or demand is high on items that you know will have a higher demand or a lower supply in the future (IE I bought a ton of corgi talismans before the corgi dragon came out and made a ton of flux) it helps to know what is in store for the game.
It also really helps to save up a bit of flux and hang out in trade chat cuz you will get somebody (like me when I quit) who comes in there that isn't really interested in selling whatever they got and selling it at super low prices