Wand Composition Theory
Authors Note: I haven't seen a proper analysis of this anywhere, so I wrote one. I am quite happy for you to use this information for your own nefarious purposes, as long as you e-mail me first and ask me politely. I spent quite a while researching all of this, so if you use it, I'd like to know.
In the Harry Potter book series, each witch or wizard has their own wand. These are purchased from wand shops which appear to be run by the artisans who make the wands, people such as Ollivander or Gregorovitch. As Ollivander says to Harry, "No two Ollivander wands are the same, just as no two unicorns, dragons or phoenixes are quite the same." As each wand created is different, it is not the witch or wizard who chooses their wand, but "it's really the wand that chooses the wizard."
Each wand has certain characteristics which differentiate it from other wands. These include length, wood, core and flexibility. Each wand specifically choses an owner, presumably someone who has characteristics that relate specifically to the wand.
I will discuss each of these wand characteristics and my interpretation of what they mean.
Part 1: The Different Wands
Knowing all the wands mentioned in the books currently is a useful prerequisite to such an analysis. As I will be referring to these below, I'll list all the wands here so you can have all the known information to refer to.
Fleur Delacour: rosewood, 9 1/2 inches, inflexible, veela hair.
Cedric Diggory: ash, 12 1/4 inches, pleasantly springy, single unicorn hair.
Rubeus Hagrid: oak, 16 inches, rather bendy.
Viktor Krum: hornbeam, 10 1/4 inches, quite rigid, dragon's heartstring.
Harry Potter: holly, 11 inches, supple, single phoenix feather (from Fawkes).
James Potter: mahogony, 11 inches, pliable (excellent for transfiguration).
Lily Potter: willow, 10 1/4 inches, swishy (nice wand for charm work).
Voldemort: yew, 13 1/2 inches, single phoenix feather (also from Fawkes).
Ron Weasley's new wand: willow, 14 inches, unicorn tail hair.
Part 2: Length of Wood
I feel that the length of a wand is directly related to the height of the person, fully grown. Hagrid has the longest wand mentioned in the books so far, 16 inches, and is the tallest person. Fleur Delacour has a wand which is 9 ½ inches, and seems to be a delicate and petite person. A wand the length of Fleur's would look ridiculous in Hagrid's hands.
Harry and James both have 11 inch wands. They are said to look identical, a characteristic that probably includes their height.
Ron's wand is 14 inches, longer than Voldemort's wand, which is 13 ½ inches. It is the second longest wand mentioned in the books. I feel that Ron, height-wise, is going to be huge.
Part 3: Wand Wood
I feel that the wood used for the wand is personality and characteristic linked. I will go through each type of wood and its owner.
Ash is the wood used in Cedric's wand. Properties associated with the wood are healing, protection, purification. It represents sea power. It is used for cleansing and removing internalised strife and conflict. Strangely, snakes fear ash trees and avoid them.
Holly is the wood used in Harry's wand. The properties associated with it are protection, luck, combat, defence, consecration and dream magic. The wood is lightning resistant. It is considered the strongest of protective woods ad guards against evil. It also symbolises life and purity.
Hornbeam is used in Krum's wand. It is considered lucky, is very good for spells and brings good fortune.
Mahogany is used in James' wand. The properties associated with it are strong protective qualities. The wood is renowned for its ability to withstand lightning strikes.
Oak is used in Hagrid's wand. The properties associated with it are endurance, triumph, strength, power, prosperity, sacrifice, wisdom, guardian, liberator and health. It increases the potency of charms.
Rosewood is used in Fleur's wand. Her name means 'flower of the court'. The properties associated with the wood are love, divination and charms.
Willow is the wood used in both Lily and Ron's wands. The properties associated with it are healing, love charms, protection, sadness, quick growth leading to a quick end, psychic energy, inspiration, emotions, dreams, rebirth, intuition and wisdom. It is also attributed with banishing long-held grief.
Yew is the wood used in Voldemort's wand. The properties associated with it are corruption, death, rebirth, transformation, great age, reincarnation, visions and exorcism. It is planted in graveyards as it feeds off corruption and death. It is considered the wood of death.
Part 4: Wand Cores
There are four currently known substances used for wand cores: Dragon heartstring, Unicorn tail hair, Veela hair and Phoenix feather. It is known that Ollivander refuses to use Veela hairs in his wand cores as they are rather temperamental.
I feel that each of the cores denotes a particular, basic personality type. The core is the more basic, fundamental measure of personality and characteristics, whereas the wand wood expands and supplements the basic outline provided by the core. Characteristics of the magical creature who supplied the core can also be found in the wand owner.
Veela hair: This is known to have been used in Fleur's wand. Her wand's hair belonged to her grandmother, a fact that adds to the evidence that a close relative's wand can be used fairly easily. Ollivander mentions that the core makes for "rather temperamental wands". Veela, as a creature, are fairly temperamental, as is Fleur.
Unicorn hair: This is known to have been used in Ron and Cedric's wands. Charlie Weasley's old wand is also known to contain this core. In the first book, Firenze comments, in regard to unicorns, "Always the innocent are the first victims". Cedric is one of the first casualties in the second rise of Voldemort.
Phoenix feather: This is known to have been used in Harry and Voldemort's wands. A phoenix's most renowned ability is the ability to live to immense age by regenerating their bodies by bursting into flame and being reborn in their own ashes. Voldemort pursues immortality, and Harry's blood is inextricably linked to his.
Dragon heartstring: This is known to have been used in Viktor's wand. I also suspect that it is the core of Hermione's wand, if only to embrace continuity. Dragons are known for their aggressiveness, a quality that Viktor certainly has.
Part 5: Wand Flexibility
The flexibility of a wand, in itself, is not a characteristic that denotes much about a person. Instead, it is more of a comment about the flexibility of the wood itself and the thickness of the wand. Krum has an unusually thick wand, according to Ollivander. At this point in time, I think that the flexibility of a wand is just an individual characteristic of each wand that its owner must adjust to, and possibly a factor in making it more difficult for a wizard to use another's wand.
In conclusion, I feel that the characteristics of a witch or wizards wand are an indication of some basic and not quite so basic information about that person, and by scrutinising those wand characteristics you can gain some extra insight into that character.