Congratulations, you've made it to Anor Londo, the city of the gods! RIght, before we proceed, ensure that you have all your weapons upgraded as high as you can, at this stage in the game, you should have enough souls and titanite to upgrade your weapons pretty significantly. For reference, at this stage we have our Zweihander upgraded to +10.
If you have not upgraded to at least this level at this point in the game, expect some pretty significant resistance as this is a fair difficulty bump.
You can go back from Anor Londo, to Sen's Fortress to reach Andre by going to the glowing Yellow ring where you entered and heading down the Shortcut.
Now, head down the stairs, ignore the giant knight and progress forwards into a giant hallway and outside into a courtyard, before doing anything else, ensure that you take a left and go down the stairs into a room with a bonfire.
Head out and left towards the two giant knights. These can be tough to deal with, but use your ranged weaponry in order to kite them one by one. Then, after killing the two, there will be two chests. The chest on the left will have twinkling titanite, and the one on the right is a mimic, so attack it and take it out to get a crystal Halberd.
Now, head back outside from where you came and head left, down the elevator. Now, head out and tackle the Gargoyle in front of you. Remember, it's weak to fire so be sure to use your Pyromancies.
Then, face the staircase that you came in at and head right and drop down to the small platform below. There, there will be a small ledge and a narrow path that you're able to walk up that leads to the next building.
Head up and roll down onto the platform below. Head through the broken window and you will be ambushed by two enemies in white- they're quick so use your parry in order to take these down quickly. Then, head up the path onto a set of narrow walkways.
Proceed carefully with your shield up, as more enemies will throw knives at you, use ranged attacks or pyromancies to get past these. Head towards the chain and attack it to drop it down for some loot to collect later.
Proceed carefully, taking out the enemies along the way. If you're having trouble, equip the Lightning Spear we picked up in an earlier area to dispose of the enemies while also keeping your shield up.
Now, head through the fog gate and turn the lever to make the elevator lower. Then, you will fight another Gargoyle. Now, head down the stairs to get to the lower level of the room we just went through.
Here you will encounter a huge amount of Painting Guardians, kite these out and clear the room. The broken chain left an item on the ground - this has Great Magic Weapon, a powerful sorcery that can enchant normal weapons.
In the corner of the room next to the panting will be the Black Iron armour set. You can't do anything in this room yet, so leave for now and head back up the stairs. Proceed towards the big staircase.
Take out the two giant knights here, they're down in two hits of our upgraded Zweihander, so you should have no trouble if your weapons are strong enough. Head through the gate to the right and head right again.
Kite out the three winged demons at the bottom one by one, then head through the path down just left of the stairs. Once you get to the bottom, there will be two winged demons, stay behind the pillars in order to not get hit by some archers.
Once they're dealt with, ensure you have a 100% physical shield and get ready to go through one of the toughest bits of Dark Souls- the Anor Londo Archers. There are two of these standing against a ledge at the top, ensure you are defending the whole time as these can easily make you fly off. Do not roll, just defend against these.
Be sure to hug the sides of the pillar here, as it is incredibly easy to fall off. Sprint up and immediately head right. Equip the Lightning Spear to deal with the Silver Knight ahead and the other one shouldn't bother you as it can't reach you.
Then, go back and head for the other knight. Once dealt with, head down the path to get a Soul of a hero, then- go back and follow the path the other knight was on and roll down a ledge and pass through the fog gate. Hang a left once inside and you will reach a Bonfire.
Then, head out and directly to the room in front of you, kill the Silver Knight inside and get 3 Sunlight Medals from the chest. Now, head out the room and to the left of the central staircase will be a Silver Knight.
Head down that path and though the first door on the left. Go to where the Fireplace is and hit it to pass through an illusory wall. Head down and head left from here to encounter another Mimic. Kill it for an Occult Club. Then, open all of the other chests to get a Full Havel's Set. Head back up to the central staircase.
Head up the first level of the staircase and go to the room to your left to encounter a Silver Knight. In this room you will find a Soul of a Hero. Then, to the right of the staircase will be another Mimic Chest.
Kill it for five Silver coins, head to the other chest on this level, which is another Mimic with a Gold coin, then head forwards toward the long hallway with the Silver Knight at the end. Dispose of the Silver Knight and then head back, and go through the door which is not locked on the left of the entrance to the hallway.
Open the door and immediately to your right will be a Silver Knight. Kill it and head up the staircase. Here there are two Silver Knights. Kill them and head to the building on the left where one of the Knights was standing. Head down to encounter Seigmeyer of Catarina again.
Open the door and immediately to your right is a Silver Knight, with two more down the hallway, you should be able to make quick work of these by now, and then grab the chest next to the door at the end of the room for two Demon Titanite.
Then, head back up and towards the left to the entrance we've not visited yet. Head down the stairs and immediately to the left is a Titanite Demon, this is pretty tough, so you can leave it for later. Head into the room opposite and go down the stairs. Take out the two Silver Knights here and open the chests for Silver Knight Armour. Open up the door here to unlock a shortcut.
Now, head back up and down the hallway we originally came from. Go up the stairs and then head down and towards the gate, dealing with the Giant Clerics, who are a bit tougher than the normal knights, in addition to the Silver Knight shooting at you. Then, push the lever to open the gate, which will serve as a shortcut to the boss. (You're gonna need this one)
If you're looking for more help, our Dark Souls walkthrough and guide can help with all other areas of the game, including the dreadedTaurus Demon, Capra Demon, Ornstein and Smough bosses. Meanwhile, we have explainers on how to access DLC Artorias of the Abyss, the best gift and best class in Dark Souls, Dark Souls' best weapons, Dark Souls Covenants, Dark Souls Estus Flasks locations, Dark Souls Titanite Slab locations and NPC quests including Lautrec of Carim.
Then, head up the stairs on the right. Head up the stairs, go through the broken window pan edrop down a platform for a Dragonslayer Greatbow, then do a plunging attack on the Winged Demon below, and unlock the gate behind you. Turn back around and towards the other Winged Demon, kill it and head into the room to encounter the Giant Blacksmith.
Head back to the Long Hallway and prepare for your next Boss Fight, Ornstein and Smough.
After these are dealt with, go up the lift and light the bonfire and head into the next room for a pretty nice reward- where you will now be able to warp between Bonfires.
From here, you will need to collect the four Lord Souls, which are found in the following locations: