I love to make myself fishtail braids, but every time I make one I am asked again and again how. So I found some lovely diagrams online, which you could have easily went and found on your own, but for the sake of making a blog post here goes:
Take the section of hair you want to braid and split it in half equally.(You do not have to tie your hair as the diagram shows, but if you've never made this braid before you might find it easier to do when your hair is tied.)
Step Two: Take a small piece of hair from the very right of the right half of hair and cross it over to the left half of hair. (You don't need to hold this small piece of hair separate, join it with the left side making it part of that half of hair.)
Step Four: Cross it to the right side, passing over the other small piece of hair. Continue to take pieces form the left then from the right until you have finished your braid.
Your finished braid willlook something like this: