My version: Not here yet!

Reference images:

Analysis (whoo, scientific): This is an insanely cool hairstyle, and we never even see the back in the movie! I just happened to come across some random behind-the-scenes shots of the back of the style, otherwise I never would've found out what it even looked like. I find it a bit baffling that some of the most complicated hairstyles are in the battle scenes and were never even seen. Seriously, who spends that much time on their hair when they're just going to get full of orc blood anyway? But to get back to topic: this style consists of three fishtail braids, continuing the Elves' penchant for that braid. The front of the hair is pulled back into one fishtail, straight down the back (you can see the part separating the middle section from the side section in pictures 1 and 3. The two side sections are also braided and are twined over the sides of the middle braid, down through the middle, criss-crossing in the back, then crossed again in the front, then again in the back (picture 2). Past that, it's kind of hard to see what they did, but it looks like the three braids are gathered at the bottom and tied off.

Directions: Fishtail braids, while beautiful, are hugely time-consuming in comparison to regular 3-strand braids. This would work with regular braids, but if you want to try fishtails, Dreamweaver Braiding has some instructions on how to do fishtail braids. Take the top, middle section of your hair and braid it, tying it off a few inches from the ends. Now take the side sections and braid them as well, being careful to keep the sides smooth and neat. Now bring the right hand braid over the right strand of the central fishtail braid and pull it through the slight "hole" that always forms with a fishtail. Do the same with the left, crossing the two side braids behind the central one. Keep wrapping them, criss-cross style, around the central braid until you read the tie on the middle braid. Take it out and retie it around all three braids. That's it!