Things You'll Need
Instructions
Decide what type of clothing you will make. This is necessary for creating a pattern and taking measurements.
Make a pattern. Lay an article of American Girl clothing on a piece of tissue paper and trace around it. If you don't already have clothing for the doll, measure her and use those numbers to make a pattern. For example, measure her height from waist to neck, from under her armpits to her waist and the length of her arms. This gives you an idea of how large a sweater would need to be to fit the doll.
Knit the pieces of the garment. For a sweater, make the front, back and sleeves. For pants, knit the front and back pieces. Use the stitch pattern of choice. Since the clothes aren't going to be very large, stick to a stitch that is smaller for a more authentic look.
Assemble the pieces of the garment. For example, stitch together the front, back and sleeves of the sweater by turning the pieces wrong-side out and making seams where needed.
Try the garment on the American Girl doll. Make any adjustments that are needed to create a good fit.