I had a couple people ask how I root doll hair.
This is the first doll I've rooted and she doesn't have holes (or it would be re-rooting). Also, her head pops off rather easily because she is a Monster High Create-A-Monster custom so I can't tell you how to get off a doll's head.
On to the tutorial!
A doll's head
Doll needles (use the smallest one; mine are from Hobby Lobby)
Hair (synthetic is what I'm using)
First draw an outline of the hairline on your doll, if it has no holes. My doll has some hair already because she's the one I started with.
Cut the hair twice as long as you want the hair to be then tie a knot in the middle and trim the ends to make it even and thread the needle with one end of the hair. If you don't know what length you want the hair, make it longer so you can cut and style it later.
Put the needle through the neck hole and line it up with the hairline. To line it up, GENTLY push the needle and feel for it with your other hand, careful not to puncture it, in case it's not lined up properly. Carefully push the needle through once you've lined it up. Gently pull the hair through until the knot meets. Do the same with the other end, which should be hanging out the neck opening. Be careful not too get too close or you'll split it and that's not good. If you split it, you have to repair it.
For the hole spacing on a MH CAM doll, use a doll with holes for reference.
I hope someone finds this useful!