Extraction for Kinah

No this does not mean taking an elite special ops team around the world recovering hostages for money, but rather making a living from collecting various plants, ores, aether etc.

"There be apples here"

The earliest proffession skill you will encounter is the gathering skill, since you begin the game with this. It starts out as the collection skill, which will take you up to level 10, at which time you ascend. When you reach that point you will begin to extract materials instead of collecting them, allowing you to gather essences from ores, plants, trees, gems and aether nodes.

While everyone can collect any of the materials, it is a tough long grind to level up extraction and is very pricey to master, easily over 2 million Kinah, people are willing to pay a lot for the rare materials that others gather.

The first goal with extraction is just to keep up with your level. Basically, everytime you see a node, you extract from it. This might take a while, especially when entering a new area and you find that all nodes are higher level than you. There is a chance you will fail on nodes anywhere 20 levels below you so it can take some time.
On the plus side however, you can gain experience from these nodes and there are some quests that give you addtional experience from gathering certain materials so if you have a good imagination, you can pretend that apple bush is a 30ft demon from the abyss (although justifying the apples you collect are epic giant swords of doom might be more difficult).

"No apples here"

Before level 10 it is not really viable to make any kinah at all from what you collect, but once you reach level 10 you can start gathering Aether, whch floats above most major towns and cities.
Level 40 nodes and above is where profits can really be started to attain, however by far the best are those that can proc. rare materials or gems, and this being said, mainly ores.
There are several hotspots that can produce gold and platinum nodes along with gems which are worth a good amount of kinah.
Of course it is better to find areas where you can farmm monsters at the same time due to being able to gather a larger number of items, including rare equipment drops for greater kinah returns.