On motown girl's website (
www.motowngirl.com) she has a hairstyle how-to section where she describes how to cornrow hair. That's where I went to learn how to cornrow. I haven't practiced enough for mine to be neat, but I found that her explanation gave good details and got me on track.
For those that don't want to go to the website:
Step 1: Decide which direction you want your cornrows to go in
Step 2: With damp hair and a comb, use a pick to gently comb your hair out then make a part in your hair. You may need someone else to help you in the back.
Step 3: With that section, take a small section in the front and separate it into three pieces: outer left, middle, and outer right.
Step 4: Place the outer left piece over the middle, and the middle piece becomes the outer left.
Step 5: As you braid, you are going to pick up the rest of the hair in that row. Make sure when you grab the hair, you drop the strand you started with. When you get to the next braid grab those hairs that you dropped instead of grabbing new ones, and so on and so forth.
Step 6: You may want to add a rubber band at the end to keep it together. I simply use my finger and twirl it around a few times. This keeps it in place until I take them out.
She also includes some other tips for cornrowing and how to moisturize them.
Hopefully this helps. Her explanation seems geared towards beginners.
Also, just so you know, these instruction came from a site on how to style natural hair. But I think the technique would be the same for relaxed hair as well.