My daughter recently came into possession of a couple of American Girl dolls (I'm a little jealous - I've always wanted one for myself), and one of them had no clothes, so I set about making an outfit for her. I've created this tutorial for the hat and vest I made (adapted from a similar pattern in a book that I believe is now out of print - The Quilted Clothing Collection by Ed and Stevie Baldwin).
If you have basic to moderate sewing skills, check it out: