I. Power in ArcanaThe more powerful members of the fae courts have access to more ancient magic then their lesser brethren- the runes of power. You may laugh now but in the hands of a skilled runecaster they are dangerous indeed. The power to shift shapes, walk in shadows, disintegrate stone or even bind others to your will- almost any gift, or curse for the reverse, can be granted provided you can inscribe the rune to describe the desired effect. Runes can be inscribed on any surface though if the caster wishes for a more long term effect something more permanent- such as stone, wood, or even flesh is preferable.
The major arcana is simplistic, one for each of the seven elements in fae lore- earth, fire, air, water, mana, light and shadow. Symbols in the seelie court will favor air, water and light, while the unseelie will favor earth, fire and shadow. The rune for mana is rarely used, there are claims from both courts that it is unstable, even dangerous, and can drastically change outcomes.
The minor arcana is where things get more complex, despite their simplistic appearance. They are what truly defines what effect the final rune will have. They come in any number of forms- representations of animals, natural phenomenon, spells, simple words or even words of power.
The direction a rune takes is also important, to a degree at least- upright (which way that typically is will vary from rune to rune) generally seeks a positive intent, while inverted a negative. The opposite of each rune can also be used to cancel, or alter, the effect. (More on this later, as it is a topic that needs examining with some length.)
II. Runic EmpowermentIn regards to runes inscribed on individuals for the sake of strengthening, weakening, granting additional abilities, removing them or even applying curses- placement is important. If the desired effect is physical ideally you would want to inscribe it on, or near, the effected area. If the effect is less tangible- possibly, but not limited to awakening, strengthening or granting magical abilities inscriptions near the mind, or heart, often work best because they are often the strongest spots of power in a being.