I think that Tolkien is ONE source on elves, and a good one, yet one must understand a few things about this subject if one is to proceed without venturing off the deep end:
These stories are myths
All language, is, at its base, metaphorical
Myths are not only metaphorical of physicality (this in itself is a difficult concept) but also of a psychological status
What we consider `fact' and `history' is just as mythical, sometimes more so, than what we take to be fiction
Given these things, here are my reactions to the typical descriptions of elves in modern Euro-culture (ala Tolkien):
Aging: My understanding is that elves are immortal. This does not mean that they don't age. This means that they do not become extinct, that they do not, in fact, die. We are talking about a subjective experience here. Immortality may be had by perfecting perception to a razor-sharp degree, in effect, slowing down the bifurcation which is known to us as `the passage of time'. I don't claim to have perfected this, yet have enough success to consider it a valid perspective.
Disease: Dis-ease is how I'd approach this one. What we are talking about here is elves in Foresthome. Lack of disease is identical to Buddhist `Nirvana', enlightenment. I would also not claim to have perfected this one, but then again, I live in the Dying Lands outside Foresthome so far. I think - mark this as a `shamanic perspective' - that one may merge with the Forest, the Faerie, the Summerlands, whatever you wish to call it, and perfect a disease-free life, yes.
Heightened sensation: Definitely a characteristic of elvenkind, yet I'd say it isn't so much from the physically perfected body as it is a state of attentiveness. Those who achieve Elder status (which can never be verified) would also be said to have `enhanced sensation' (i.e. certain yogis, Masters, etc.).
Beautiful appearance: Aside from the relative definition of `beauty', I'd have to say that elves, in general, are more healthy than humans, on the whole. They radiate a certain joy and well-being which others see as `beauty', when in fact it's simply an attunement to one's deeper self which brings this effect about.
I must add that I think that the label `human' is just as mythical as that of `elven' and that both are poorly understood. To assume one knows oneself and then calls this self `human' is not to really understand oneself at all. To answer another post which asked for my delineation between elves and humans, I'd respond by saying that I think that certain humans can become. This is not unknown in literature, yet does not require literature to substantiate it.
I tend to think that humans are more like pupae; to the elven butterfly, or caterpillar to the elven pupae; (from which dragonflies are born).
Categorizations of `Christian' or `Buddhist' compare well here. One could claim that these describe only `mindsets', yet how can one counter the argument that mindset makes the individual, that being is directly affected by thought, and that one's self-concept (however abstract) allows one's choices in future incarnation (evolving self-images).
This gets very complex very quickly. I tend to agree with what Buddhists say about the illusory view of the `self'. I also think that most religious terms are metaphors, not literals. Even enlightenment, itself, refers to a metaphorical `state', not some sort of different condition. Reincarnation is the replication of the self-concept. Liberation is what happens when one becomes Immortal, becomes an elf, if you will, and we call it by many names.
The most astounding difference between elves and humans lies within their psychology and their magick. Elves tend to stay away from dogma, rigid mental concepts, and literal `truths'. Humans tend to need these things as structures of support. Elves tend to be less attached to the things of the world, are more contented, being immortal, with patience and kindness, and they are playful in a genuine way. Elves are also often the most empathic, due to their depth of experience, their value of those things which do not change, and their direct connection to the natural, the spontaneous, the unrestricted.
Elven magick is often not visible to the untrained eye, passes, more often than not for `natural phenomenon', and is much less control-oriented than human magick. There is much in Tolkien and others, that I think worthwhile regarding elven magick. I've been studying it for some time and think it will be a lifetime study. There is no end to the self for the self. Elven magick is too complex to encompass.
Most people focus on simply the physical characteristics of mythical beings. They do not see the incredible depth which these beings make available to our experience through our identification.
Fantasy and reality may be mixed in a pleasant and valuable way.
The Age of Reason is over!
Exerpt from the Ballad of Tinuviel
From "Lord of the Rings" by J. R. R. Tolkien
"The leaves were long, the grass was green, the hemlock-umbels tall and fair,
and in the glade a light was seen of stars in shadow shimmering.
Tinuviel was dancing there to music of a pipe unseen,
And light of stars was in her hair, and in her raiment glimmering.
There Beren came from mountains cold, and lost he wandered under leaves
And where the Elven-river rolled he walked alone and sorrowing.
He peered between the hemlock-leaves and saw in wonder flowers of gold
Upon her mantle and her sleeves, and her hair like shadow following.
Enchantment healed his weary feet that over hills were doomed to roam;
And forth he hastened, strong and fleet, and grasped at moonbeams glistening.
Through woven woods in Elvenhome she lightly fled on dancing feet,
And left him lonely still to roam in the silent forest listening.
He heard there oft the flying sound of feet as light as linden-leaves,
Or music welling underground in hidden hollows quavering...
Now withered lay the hemlock-sheaves, and one by one with sighing sound
whispering fell the beechen leaves in the wintry woodland wavering.
He sought her ever, wandering far where leaves of years were thickly strewn,
By light of moon and ray of star in frosty heavens shivering.
Her mantle glinted in the moon, as on a hill-top high and far
She danced, and at her feet was strewn a mist of silver quivering.
When winter passed, she came again, and her song released the sudden spring,
Like rising lark, and falling rain, and melting water bubbling.
He saw the elven flowers spring about her feet, and healed again,
He longed by her to dance and sing upon the grass untroubling..."
Song to the Lady from "Lord of the Rings" by J.R.R. Tolkien
Snow-white! Snow-white! O Lady clear!
O Queen beyond the Western Seas!
O Light to us that wander here
Amid the world of woven trees!
Gilthoniel! O Elbereth!
Clear are thy eyes and bright thy breath,
Show-white! Snow-white! We sing to thee
In a far land beyond the Sea.
O stars that in the Sunless Year
With shining hand by her were sown,
In windy fields now bright and clear
We see your silver blossom blown!
O Elbereth! Gilthoniel!
We still remember, we who dwell
In this far land beneath the trees,
Thy starlight on the Western Seas.
A Elbereth! Gilthoniel!
O menel palan-diriel
Le nallon si di'nguruthos!
A tiro nin, Fanuilos!
Paths and Possibilities