In Tree of Savior, character progression is highly dependant on the amoun of silver coins you earn. Indeed, classes have certain attributes that can only be leveled through the use of the in-game currency. Moreover, if the best equipment can be obtained as loot drops or crafted through recipes, upgrading them will require a large amount of coins. Add to this the fact that players will be using a lot of pots, and you will more often than not find yourself wanting more and more silver coins.
Thankfully, there are a few area in the game where you can farm mobs for silver coins, equipment drops (meant to be sold), and non-negligible exp gains. One of the best farming areas, especially for players in the level range of 20-40, is Miner's Village.
Miner's Villages in fact has two farming areas:
What is special about these areas is that they have a sort of mini-boss, the Large Red Kepa, and usually a large number of regular monsters known as the Red Kepa's that for some reason or another have a high drop rate for certain pieces of equipment.
Once you get closer to level 30, your character will easily be able to earn 15,000-20,000 silver coins in half an hour. It can even take less time if the area has afk bots (and there's usually a lot) farming the Large Red Kepa as they don't generally pick up their loot, which ends up being available for you to pick after some time.
If you encounter too many active players around the Large Red Kepa, you may want to switch do different channel where you can farm the mobs unhindered.