Make a seam. Iron (or finger press) the seam open. Working from right to left (if you’re right-handed) on the face of the garment work a back stitch where the stitch showing on the face of the garment goes over 1-2 threads leaving a little tiny stitch showing. On the back the stitch will be much longer.
This will hold the seam allowance down on the inside of the garment (between the fashion fabric and the lining). This will help the seam to lie better and prevent unnecessary wear and tear on the seam allowance.