Early Game - World Loot and The Inscription Table
The world will be full of magic loot, from resources to scrolls to equipment. In the early game, looting structures will be your primary source of scrolls. Scrolls will be much more common and powerful in magic structures.
Beginner spell books can be found or crafted. In order use spell books, you will need to bring scrolls to the Inscription Table.
However, these early spell books will have limited slots and will be lacking attributes. Better spell books should be crafted or found by getting into mid game.
An early game source of additional mana is the Wandering Magician armor set.
Mid Game - Powering Up
Upon reaching nether level resources, you will unlock an entirely new dynamic to gaining power: The Scroll Forge
The Scroll Forge is used to craft scrolls by using ink, paper, and a focus. The ink determines the rarity (and therefore level), and the focus determines spell’s school.
Intermediate spell books can be crafted using nether resources (ex: Apprentice’s Spell Book).
You should also start to craft stronger armor using arcane cloth. In order to get high quantities of arcane essence, you will need to focus on raiding magical structures.
In order to continue progressing, keep an eye out for runestones in magical structures. Runestones are used to craft more powerful armor.
Late Game - Unlimited Power
Late game is reached by obtaining netherite and vast quantities of basic resources, and is powered by the Arcane Anvil. The Arcane Anvil is the most powerful crafting station, used to level up your scrolls, upgrade armor and spell books, and imbue weapons with spells.
Farming basic resources is done most effectively by killing the Dead King boss.
School armor will allow you to specialize in a particular element (ex: Cryomancer Armor).
Upgrade Orbs are crafted using Arcane debris and Cinder Essence. By default, you can only upgrade an applicable piece of equipment three times.
Along the way
At every stage of your adventures, be sure to keep an eye out for rings, unique spell books, named spell books, and magic resources!
Arcane Essence will be the most required material, but is also the most common.
Runestones are more rare, but are most often found as a reward for killing a miniboss or in magical treasure chests.