the best way to make adenaa now is leveling new characters over and over to get adena from low level areas such as cruma tower, enchanted valley, forest of dead, etc.
farmers are doing this already. low level areas are the mine of adena now.
Make Summoner/ISS/Fortune Seeker. you don't need shots on a summoner but if you need extra damage they are cheap from pet manager. Buy 30,000k+ SSR on your spoiler and you should be able to make at least double what it cost by the time they are gone by selling mats and drops. Save all event pouches and sell them in town for 150-250k.
If you need fast adena buy traces of kartia from the ncstore and sell them to a dwarf for 45-50kk each, or put them in AH for more and wait for them to sell