I highly recommend Gael Baudino's books in the Strand's Series. The link to the series also contains information on the physical aspects and powers of the Elves - their ability to change reality in nearly any way (though anything in depth of far-reaching greatly drains them so Vanessa certainly wouldn't be doing anything large), their extreme coordination, supernaturally keen senses, etc. - should anyone be interested or need to know for purposes of interaction.