First, you'll need some hair bands, pins for your hair and some type of hair bun tool that you are comfortable using. I've tried the big thick hair bun things you can buy at your local drugstore, but I didn't like it too much. I use a plastic hair bun "creator" tool - I am pretty sure I got it at Walgreens and it's awesome!
So, first brush or comb your hair and prepare to have it up in a high pony tail. As you gather your hair for the pony tail, take a section from the front part of your head and separate it from the pony tail hair. The section should go two to three inches back towards where the bun will be. Keep the rest of your hair in a pony tail (loose one is fine) as you work on the small section.
French braid the small section of hair and finish it off by braiding normally for a few inches more. Then, regather all the rest of your hair for your high pony tail and take the braided section and include it with the rest of your hair. Smooth out sides as needed - put it in a nice firm pony tail. Then, take out the bun making tool (or make a normal bun however you prefer) and make your bun! That's it!
With the bun tool I use, I put my hair in a pony tale, then take the hair and pull it through the center of the plastic, then roll the tool inward and hook the sides together. Then move my bun around to cover up the plastic pieces. Then, use pins to make it extra firm and us a little hairspray to keep the hair in check! You're done!!!