Harvest Valley & Earthen Peak
Souls: approximately 14,952
Farming souls at Harvest Valley & Earthen Peak, Dark Souls 2: SotFS
Harvest Valley is not ideal for farming souls because it's filled with poison. Being inflicted with the poison status effect means that you must pop a bunch of Lifegems to counteract the poison, possibly wasting a thousand souls or more. You're trying to farm souls, not spend them.
Start from the Poison Pool bonfire. Equip the Covetous Silver Serpent Ring+1, the Bracing Knuckle Ring, and two-hand the Greatsword. A Raw Greatsword+6 is recommended. Run through the first poison area. Avoid fighting in a poison area if you can. Head to the area before The Mines bonfire, where you can find Desert Sorceress x 2 and Undead Laborer x 5. A skeleton from the first poison area might follow you. Don't fight a Desert Sorceress head on. Snipe with bow and arrows from a distance where her fireballs can't reach you. Rest at The Mines bonfire.
Head to the narrow passage where a Mounted Overseer can be found. Go into an adjacent area containing a bunch of Artificial Undeads and an Undead Laborer. Funnel the enemies through the narrow passageways to allow you to fight one or two enemies at a time. Take care not to drop down into the various poison caves. If you happen to be in a poison cave, use the torch to increase your visibility and make your way out of the cave as quickly as possible. Ignore the Mounted Overseer x 2 in the second poison area. Fight the Undead Steelworker who stands on a wooden bridge, but be wary of fireballs raining from above. A Manikin is ambushing you from above. A further Undead Steelworker x 3 can be found in the room before the boss arena of the Covetous Demon. Let them smash through the various poison pots to poison themselves and wait for them to die from the status effect. Before the boss arena stands a Desert Sorceress. Use a ranged weapon to deal with her. Kill the Poison Horn Beetle x 2 near her. Another Manikin is trying to ambush you from a corner. Nearby is an Undead Laborer sitting, facing various poison pots. An adjacent room has an Undead Supplicant and Poison Horn Beetle x 2. Rest at the Lower Earthen Peak bonfire.
A Manikin is hiding behind a wooden chest. A further Manikin x 2 are standing on a stone bridge, one of them is an archer. Use a bow and arrows to snipe them. Go up an inclined plane to trigger a Manikin to drop down and an Undead Steelworker to approach you. Get rid of the Manikin as quickly as possible before the other enemy reaches you. The Undead Steelworker would most likely be poisoned from breaking the various poison pots. At the other end of a stone bridge stands a Grave Warden. Use a ranged weapon to lure this enemy to your position and fight him there. Approach a wooden ladder to bait Manikin x 2 to drop down. Get rid of the first Manikin as quickly as possible before the second arrives. Climb the ladder to find a Grave Warden standing in front of a windmill. Rest at the Central Earthen Peak bonfire.
Ascend an inclined plane and locate Manikin x 4. One is at the top of the inclined plane. The other three are ambushing you from above. Climb a ladder to find a Manikin archer at the end of a narrow passageway. Desert Sorceress x 2 are standing nearby, one of whom is hidden in a corner. A Manikin is hiding in the pit below. Manikin x 2 are hiding behind a bunch of poison pots. Go along a passageway to find a Grave Warden. A Manikin is standing on a ledge above, trying to ambush you. Ignore the Grave Warden at the far end of a broken bridge. Turn a corner and find yourself on a path outside, where a Manikin and an Undead Laborer are located. Head inside and climb a ladder to find a Desert Sorceress standing on a balcony. Proceed along a passageway filled with poison pots, snipe a Suspicious Shadow who is clinging to the ceiling, backtrack, and let the enemy be poisoned by breaking the pots. In one corner is a Desert Sorceress. In the other corner are Undead Supplicant x 2 and Grave Warden x 2. Rest at the Upper Earthen Peak bonfire.