Begin by parting the hair down the middle as if you were going to make pigtails. Put a temporary band in one side to keep it out of the way. If your part is really straight down the middle, it doesn't matter which side you start with. If you have made a side part in front (angled to the center and straight down the middle in the back), put your temporary band in the side that has the smaller section of hair in front. Your first braid will be on the side with the most hair.
Gather the hair as if to make a low pigtail, and brush it smooth. Divide it into three equal sections.
Braid the hair. For the first crossover, use the section of hair that comes from near the forehead. Continue braiding down to where the hairs start to get short and pop out. Secure it with a hairband.
Repeat on the other side. If you have a side part in front, you should be able to braid down a farther distance before the shortest hairs start popping out. Instead of going down as far as you can, try to match the placement of the hairband in the first braid. Otherwise you'll have one long braid and one short braid.