Hair Tutorial: Half-Up Fishtail

This is my first ever attempt at a tutorial of any kind, so here goes.
When I have second (or even third) day hair, I like to have it half up rather than all down just because it gets in the way.  This is a way to keep it out of my face, but its got some more going on than just being stuck up with some bobby pins.
If you don't know how to fishtail, fret not! The way I fishtail for this style is the same way I fishtail when I'm putting all my hair in one braid.  I find it much easier than some ways I've been taught before.
This style looks best when you've got some texture in your hair (thus the old hair rather than freshly-washed hair.)

I curled my hair yesterday so it's still a bit wavy from that.
Step 1: Take a piece of hair from each side of your head.  You can take the piece from wherever depending on where you want the braid to fall.  I usually take it from right behind my ear because I like the braid to start right at the base of my head.

Now here's the difficult braiding part.
The way I do it is to divide one of the piece in half and pull half of it across my head to the other piece and gather it all together so that you have a piece and a half on one side and half a piece on the other (does that make sense?  It's the best way I could think to put it.)  Then you repeat on the other side - divide and bring the divided piece across to the opposite bundle of hair. That's it! You just repeat that over and over until you get to the end of your hair bundles - or earlier, depending on the look you want.  I usually go all the way down and secure with one of those tiny clear elastics.
Here's step by step with pictures:

If you want a more piecey, fishtail-y look, divide your bundles into smaller pieces that you bring across rather than just dividing in half every time.  If you get the chunks too big, your fishtail will end up just looking like a regular braid, which is a bummer when you worked for a fishtail.

That's it! This is also a good building block for more intricate styles like updos or really fancy half-updos (I may do an updo tutorial with this next week) :)
Sorry for the bad photo quality, I didn't have anybody to take pictures so I used a self-timer on my phone.
Happy fishtailing!