Purchase the Tower Key from the Shrine Handmaiden and take the stairs to exit Firelink Shrine near a twisted tree, which sometimes can be examined for a Seed of a Giant Tree , and then collect the Soul of a Deserted Corpse near the locked gate.
Take the spiral stairs and cross to the opposite tower and then take the lift to find the Fire Keeper Soul .
Head back down the lift to find that Patches has locked the gate behind you and then look down the tower to spot the Fire Keeper Armor Set . You'll need to roll off the ledge to land on the stones protruding from the wall and then make your way to the bottom of the tower to collect the Estus Ring .
You can now exit the tower and return to Firelink Shrine, head back up the stairs to find Patches in the corner. If you choose to forgive him, Patches will become a permanent merchant in Firelink Shrine and after refreshing the area you'll obtain the "Patches Squat" gesture from him.
Note: The Fire Keeper Soul can be given to the Firekeeper to allow you to heal Dark Sigils. Don't do this or it will anger Yuria and mess up the "The Usurpation of Fire" ending. This is also required for the ending "The End of Fire".
Speak with Anri of Astora and Horace the Hushed on the steps and then head back to the spiral stairs to reach the bridge. This time you'll want to fall off to the left to reach the roof of Firelink Shrine with a nest containing an NPC that'll exchange certain items for better items.
Check the rooftop for some Homeward Bone x2 and then search for an archway that leads into the rafters to collect an Estus Shard . Don't leave just yet though, because you can cross the rafters and strike the far wall to reveal a hidden area with the Covetous Silver Serpent Ring .
Drop back into Firelink Shrine and then return to the rooftop again and look behind the building to spot a Crystal Lizard to obtain a Twinkling Titanite .