High Wall of Lothric

This is the second area of the game, right after the tutorial boss. Enemies are much tougher than those found at Cemetery of Ash. The enemies you should be wary of are Pus of Man and Lothric Knights. Some regular hollows would transform into Pus of Man once you are close enough to them. The first time you defeat a Pus of Man you would be guaranteed an Ember. Each Pus of Man also drops upgrade materials. However, at this early in the game, fighting any Pus of Man is tantamount to suicide and it's not worth your time and effort. Lothric Knights are more manageable than Pus of Man. Spend some time fighting and farming Lothric Knights because they drop upgrade materials in addition to their weapons and armour set. Farm Lothric Knights as shown in the video below.

2. High Wall of Lothric, Dark Souls III

Once you reach the area that spawns a Lothric Wyvern who breathes fire on a bridge, underneath the wyvern is a room containing the first Mimic in the game. Leave the Mimic alone for now. Later on, you can use that first Mimic to farm a Symbol of Avarice. Proceed to the Tower on the Wall bonfire and light it. You will need this bonfire in order to quickly rescue a merchant NPC. On a rooftop near the bonfire is a Crystal Lizard that drops a Raw Gem. Kill that lizard as quickly as possible before it runs away and disappears. In case the lizard disappears, return to the location where you first saw the lizard, quit to menu, load your game, and you should see the lizard again. Be sure to grab the following items:

• Two Gold Pine Resins. These will be used to fight the area boss.
• Two Undead Hunter Charms. You will need these to farm a Symbol of Avarice as shown in the video below.
• Broadsword. This will be your main weapon during this area and some areas ahead. When you have the chance return to Firelink Shrine, talk to Andre, and have him infuse the Broadsword with the Raw Gem you obtained from the Crystal Lizard.
• Claymore. This will be your secondary weapon for dealing with difficult enemies later in the game. At the moment, you don't have enough stats to properly wield the Claymore. As you progress, regularly pump a few stats into Strength and Dexterity. You need exactly 16 Strength and 13 Dexterity in order to properly wield the weapon. You would need to farm a Raw Gem for infusing your Claymore. The Claymore is guarded by a Lothric Wyvern who breathes fire at you whenever you're in front of it. Do a suicide run if you must to collect the Claymore. Remember to spend all your souls first before making the suicide run.
• Cell Key. You require this key in order to rescue Greirat.
• Estus Shard. With this item, Andre would upgrade your Estus Flask to allow you an extra use.

Refer to the following guide for tips on farming for a Symbol of Avarice. Read the section "Symbol of Avarice".

https://steamcommunity.com/sharedfiles/filedetails/?id=2101033317

3. Symbol of Avarice, Dark Souls III

Use an elevator to help you unlock a shortcut near the High Wall of Lothric bonfire. Warp to the Tower on the Wall bonfire, explore the basement underneath, and rescue Greirat from there. Return to Firelink Shrine, talk to Greirat, and purchase a Light Crossbow from him if you don't already have a Light Crossbow. Don't forget to purchase at least 100 Standard Bolts. Perform the "tree jump", run to an elevated platform near Sword Master, and use the crossbow to easily kill him. Once defeated, Sword Master would be available to be summoned to co-op with you against Vordt. Lion Knight Albert is available to be summoned for co-op against Vordt regardless of whether or not you kill Sword Master. Killing Sword Master now (before you fight Vordt) means that he would also be available to co-op with you against a late-game boss.

Prior to fighting Vordt, talk to Emma and exhaust her dialogue. For now, she would give you an item required for progressing to the Undead Settlement. By now, you should have at least a Raw Broadsword+1. Be in Embered form, summon Albert and/or Sword Master for jolly co-operation, buff your weapon with Gold Pine Resin, and fight Vordt.

In case you want a few extra levels before fighting Vordt, refer to the farming video below.

Farming souls: High Wall of Lothric pre-Vordt, Dark Souls III