Lothric Castle

First things first, head back to the Dancer of the Boreal Valley bonfire. From there, climb that ladder you've used before. This time, when you reach the fork, take the left path. This leads you towards the Consumed King’s Garden.

Once you're in the Consumed King's Garden, find the building on your right. Instead of doing what you might have done before, this time ride the lift all the way to the top.

As soon as you arrive, check the base floor. You'll find a valuable Titanite Scale here. Grab it!

Now, head up the stairs. You'll run into a couple of Hollow Slaves. Deal with them, then keep going up another set of stairs. Up here, you'll find some Lothric Priests. Take them down.

After clearing out the priests, you can grab a Titanite Chunk. Then, open the door nearby. This will lead you back towards the entrance area of the Consumed King's Garden.

Okay, let's backtrack a bit. Head back through the Consumed King's Garden until you find a side room. Inside, there's another Titanite Scale waiting for you, along with more Lothric Priests.

Now, pay attention: from where you found that last Scale, enter the room directly across from the ladder. Inside, you'll face a Lothric Knight and another Lothric Priest. Your priority here is to rush the priest. If it starts buffing the knight, things get much tougher. These knights are tougher versions of the ones you fought on the High Wall, with more health, but you should be able to handle them if you focus the priest first.

After you've dealt with them, you'll find a Soul of a Crestfallen Knight on an altar. Collect it.

Enter the next room. You'll see stairs leading up. Wait at the base of these stairs for another Lothric Knight to approach. It's best to back up into the previous room to fight it. This way, the Lothric Priest you might have missed or that's still alive in the other room can't interfere or buff it.