As I promised @fromsiberia, some step by step pics from attaching hair to me next doll
This is before and after of steaming the hair. Depending on your yarn, hook size, and tension you might not need this, but I'm making Huan Cheng and not little orphan Annie!
I started with a pin in the center of the hair base and place it in the top center of the head, then make sure it's all facing the right way.
Stitch the hair base down around the edges. You don't have to go every stitch. Do a couple stitches in the middle, too.
His hair was in two layers, so I put the second one up in a rubber band and pinned the first one in place. I use one stitch per pin to hold the hair down, I like it to be a little flappy.
For bits like bangs, you might want to sew them a little differently. I sewed closer to the tips to tame them a bit, since they didn't have the full weight of a long strand holding them down.
Don't mind the bald spots, they'll be covered by the second layer.
You can sew one level of pins around, or one strand at a time. Doesn't matter.
Second layer of hair pinned down. See? I told you the bald spots would be covered!
I added one more layer of six strands to bulk up his hair a little, and he's done!
I hope that helps for your future endeavors!