Things You'll Need
Instructions
Measure the doll. Just like with a people pattern, you need to measure the doll's body at critical fitting areas: waist, chest, neck, arm from shoulder, elbow from shoulder and wrist. Once you have those measurements, draw a basic body, collar, sleeve and wristband pattern on your pattern paper or scrap muslin, adding half an inch seam allowance on all sides.
Make a mock-up. Once you have your pattern drawn, cut it out of some scrap or cheap fabric and stitch it together. Try the shirt on the doll and note what fits and what does not. Tweak your pattern and restitch until the body and sleeves basically fit the doll, bearing in mind that a child with small and clumsy fingers will likely be the one dressing and undressing the doll the most. Is the shirt pattern loose enough to take it on and off easily?
Modify for different designs. Think about ways to modify the basic pattern: button placard in front, no-button peasant blouse, large sailor collar, no collar, long sleeves or short sleeves. Try all your modifications with cheap fabric scraps. Once you know a certain collar or sleeve length works on this doll, clearly label the piece and set it aside. In no time, you will have a collection of pattern pieces that work together, fit the doll in question and can be mixed and matched for infinite shirt designs.