There is so much information available on how to efficiently farm and make banks. It was a bit overwhelming for me as I just got back to PoE this league. I started around the time when the incursion race began (20 days ago), and 4 days into the race, I noticed that there was this guy with a headhunter and a full set of gears on the top of the ladder. I was very curious about how he amassed so much fortune in such a short time. I wanted to know what he did, so I decided to try out every method of farming PoE Currency to see how I could farm as efficiently as these top tier players.
There are lots of ways to make currency.
mapping
General mapping and drops from maps
Setup your syndicate members to give the desired drops (for me it would be sulphite scarabs to open up your mine to get additional sources or drops)
Do prophecies from time to time, they will most likeley proc during mapping and some of them are worth quiet a bit or are useful.
delving (from A.2.) farm azurite to upgrade the stats of your crawler/equipment to get a comfortable delving experience. Go down to reach deeper levels and better chances of rare encounters.
You should also try to look in each corner for fragile walls, and the fossils they might contain. I would guess I made like 200c just by selling fossilsso far.
Farming lab
for valuable enchants on meta-helmets or all-time-favorites like "Starkonja's Head"
maximum amount of treasure keys
special encounters (also from A.2) Special scarabs OR the incursion temple might bring up some opportunities for making money.
Breach research rooms / scarabs for running Breachlord's Domains (also upgradeable throug "It That Fled" in Research safehouses)
Harbinger orbs from syndicates/zana to fun higher tier maps (or stock up your atlas completion). Also gives you a chance to get am beachhead map.
Farming Atzirto sell itemdrops and uber fragments (this also counts for shaper fragments and his guardians; depending on what you are able to farm)
chaos recipe (nice and easy while running atziri, lab or maps)
These are all useful methods of getting PoE currency if you are just starting out in the game. It can be overwhelming at first, and there are a lot of varying pieces of advice out there on the best ways to get as much currency as you can. However, the best thing to do is to find the right method for you, and do one that you are willing to put your time into. If you don't want to waste too much time, you can choose a reliable PoE Currency Shop to buy poe currency, https://www.igvault.com/POE-Currency is a reliable poe currency store, cheap prices and fast delivery.