Requirements
There are no quests required for you to start up gaining arceuus house favor in OSRS. There are also no items, teleports, and even skills required.
However, you may want to do the Rune Mysteries quest for additional XP, and you might want to have weight reducing armor as well as three stamina points as these are recommended items.
For miscellaneous, to make things a lot easier, you may also get the RuneLite game client. With the RuneLite game client, this process will be faster up to five times the usual speed.
How To Get There
You will do everything in the north of the Arceuus bank in the Arceuus Library. To get there, if it is your first time, keep running west then cross the bridge.
Go northwest until you arrive in the Arceuus Library. You may want to bring 80,000 GP and go north of the library to see the fairy ring.
There is an NPC in this area. Pay the NPC here to unlock the fairy ring in this location. This fairy ring is in a great spot because it is also near the dark altar.
Starting From Zero Favour
Starting from zero, you should make sure that you have 0% or that you have locked in 100% favor in other houses. If you don’t, you will lose the other houses’ favor. You may start the AA miniquest for you to do this.
Library
The first thing you need to do is go to the center room on the main floor of the arceuus library.
There are four corners wherein there is an NPC on each. You need to help three of these NPCs. You right-click help for each. You avoid the NPC on the northeastern side. These three NPCs are Sam, Gracklebone, and Biblia. What they will do is ask you to bring a scroll or to bring a book. You can only help one of these NPCs at a time.
For the next step, ensure that you have the RuneLite library plugin and turn on. When you go to rooms with bookshelves, you will see white squares, which would show you the possible locations of the book that you are looking for. This will be a trial and error. You need to go around and try each one. Search each square until you find the book or the scroll that the NPC is asking for.
Return to the NPC who asked for the book when you find it. Grab more books as you go back. Talk to the NPC, and the NPC will trade the book that you found that it asked for for a book of arcane knowledge. Read the book. You can select a magic experience or crafting experience. For every book that you will turn in, you will get 2.5% of Arceuus favor. You need to do this until you reach a 100% favor.
You need to alternate between the three NPCs to have more Arceuus favor. Repeat over and over until you are at 100% favor. When you find the books, A Soul’s Journey and Transportation Incantations, you should read them both. A Soul’s Journey will unlock the Bare Your Soul miniquest, and the Transportation Incantations book will unlock teleports.
House
With RuneLite, you will get to finish everything in just less than an hour. You will find a house down east of the library. You should enter this house and there you will see Arcis, an NPC. Talk to Arcis, and this will unlock your 100% Arceuus favor. However, this will only happen if the architectural alliance miniquest is unlocked. You should go to the front of the current castle to do this where there is Hosa, another NPC.
Talk to Hosa and select the first option. There you will have the quest unlocked. Go back to Arcis and lock in your Arceuus favor that is at 100%. And there you go, you have finished everything, and you have locked in your 100% Arceuus house favor.