One tip to help manage the hair of your American Girl doll is to use a wig brush. This type of brush has a rubber base and metal teeth. The American Girl company sells a small version of this brush, but a regular wig brush will do just as well. Additionally, you may find that a normal sized brush is easier to use than the smaller sized brush.
In addition to having a wig brush to use, many people find that it is useful to use a detangling spray. You can purchase either regular detangling spray or make some of your own by mixing water and fabric softener. One thing to note that if making your own, it should only be used on the doll and not for human hair.
One last tip to help manage your American Girl’s hair is to never use your own personal brush on the doll. This will transfer oils from your hair to your doll and make it more likely to attract dirt.