Sewing up seams

Every time I sew up a garment, the seams are thick and chunky and uncomfortable. What method should I be using?
Lynne Strode, Basingstoke

My favourite finish is a mattress stitch seam, sometimes called ladder stitch. This method gives a flat seam and makes it easy to match patterns as you work from the front of the knitting (right side facing). This method is where you pick up the bars between the first and second stitch from the edge of your knitting on one side, and then go across and do the same on the other side, creating a ladder of thread between your two pieces. Leave the stitches loose for a few repeats, then gently pull the yarn and, as if by magic, the knitting will slot together.