Rune magic in the Vanessa Kinley, Witch PI Series world (Crossville Supernaturals) is, naturally, based on runes used historically by the Germanic cultures of central Europe and Scandinavia.
Runes alone are not enough. The magic is activated by special marks (called incantation lines or marks) drawn in certain key points along the rune. Accuracy is key. A misplaced incantation mark can change the spell's intention completely, rendering it null or wild, or pushing the magic in ways the witch did not intend.
Aside from accuracy and intent (for the witch must focus absolutely on their intention), the next key element for successful rune magic is patience. Rune magic takes time, depending on the spell or ritual being invoked. Nessa's Illumination spell, pictured above right, involves four simple strokes: three straight lines for the lightning bolt-like rune Sowuli (sol, sun) and a circle as the incantation mark. Nessa places her hand over the rune to activate the spell, though other witches with more formal training use different methods to invoke the rune's magic.
Some spells or rituals are so complex, however, that they involve numerous runes as well as other, more traditional trappings of witchcraft, such as herbs, wands, and even blood.
The strength of the spell depends on the focus of the witch as much as on his or her particular latent talent or strength. But the point of speed is immutable: rune magic takes time to work. That's it's biggest drawback.
On the other hand, it tends to be more stable and reliable than other types of magic.
Some incredibly disciplined (and, frankly, cunning) witches have gotten around the speed problem, which will be a factor in Black Witch Rising (Nessa, Book 3).
A Slow Learning Process
Finally, rune magic, like all magic, takes time to learn and master.
While Auntie O and others conspired to hide Nessa and Nick's magical talent from them, Nessa's time funneling what little magic she could access taught her the focus she will later need to perform more difficult spells.
In A Witch and Her Familiar (Book 2), Nessa works toward refining her control over a version of the Healing spell she used near the end of Between a Witch and a Hard Place (Book 1), shown above left and center. The different versions are for different levels of healing.
And remember that incantation lines help differentiate the uses of runes for divination from the uses for spellwork.
Because her magic was hidden from her for so long, and because of Nick's negative reaction to magic, Nessa struggles to work this slightly more complex spell. It's a frustrating process for her, but naturally so. No one runs before they crawl, no matter how talented they are. There's a process to learning. Magic is no exception.
I'm sure Nessa will learn more runes as the series progresses. Nick will likely learn some, too; as a chaos witch, he can draw from multiple sources, including runes, which makes his magic much more dangerous and flexible than Nessa's.