Elves: size matters

Elves have a long history in folklore and fantasy novels. They have their roots in a shoe-mending tricky/mischievous/annoying/Norse mythos. Over time elves have grown considerably taller and considerably more badass. When they grow to be over four feet tall, they shuck their shoe-mending ways and around six feet, they become ethereal and perfect beings. The image of tall elves, distant and cold, is pushed most strongly by old and new success of the Lord of the Rings. But there is an upper limit of acceptability for these tall elves. If they are more than seven feet tall, you may be stepping into a weird alien race or lanky giant territory, and things go downhill quickly if they get any taller still. Imagine if the fifty foot woman claimed to be an elf? Yeah, it's kind of like that.

But there are still many elves who start stick to the short end. If they are too short, they tend to be a little silly. They can pass for tricksy or servile, but they may also confuse the reader into thinking they are very large fairies. One of the main problems is that an elf who is too short eliminates all chances of a satisfying interspecies romance with a human character.

Around five feet and you start getting some potential. If they are just a little short they are fighting from a height disadvantage, and have more to overcome. They can be more badass than tall elves, because their success in battle in a tall world displays character strength. This height may be optimal.