For tiny doll clothing made from fine knits, it is a good idea to test your sewing machine to see which method works best for you. Take a scrap of your fabric, double it so there are two cut edges together, and test sew it on your sewing machine, checking the tension, and the effect your choice of a straight, zig-zag stitch or overstitch will have on the visibility of your seams.
In the photo above I want to make very narrow seams for my 1:12 scale doll, so I laid the fabric pieces on a piece of printer paper (you can also use plain tissue paper) to hold the seams and keep them from jamming in the throat of my sewing machine. I stitched both zig-zag stitches over the edge of the seam, and straight seams to see how my machine handles this fine fabric with very narrow (less than 1/8 inch seams).
