Magic

Although runecrafting has yet to be implemented, you can very easily obtain runes from almost every kill. You must first have a staff, which you must be creative in obtaining. If you use CustomRecipes, you can just write one in. I've gotten it to work just fine.

Staff in hand, you must first open your spell book (ctrl+C), and click on the spell you wish to cast. At first, the wind bolt is your only option. Once you've made some kills with your spells, you will gain experience, and levels, increasing the number of stronger, and more useful spells you can use. Elemental staves have not yet been implemented.

Hint: Don't go after anything big at level one. Even a zombie will take forever to kill, and death is the only way you gain experience. Try chickens.