sewing.
Collars
Baste, using long hand stitching, down collars before pinning the facing to the neck edge. This keeps the collar from shifting during machine sewing. The collar stays where you want it. I usually use contrasting thread so I can easily see the basting stitches to remove them.
Zippers
After machine basting the center seam where you are placing the zipper, press open the seam. Next hand baste a zipper (regular zippers; not particularly invisible zippers) using the guides on the zipper and contrasting thread. Turn the garment to the right side. Sew the zipper using the basting stitches as a guide. This will make your stitches more even on either side of the center seam.
Let me know some of the other things you baste. Whether you are making doll clothes or an outfit for yourself, take the time to baste, baste, baste!