Somethings to know before you begin:
Sewing French seams can require a tiny bit of math to make sure your final seam allowance is correct.
In the examples below I have a total seam allowance of 1/2 inch, so my first stitching line is 1/4 inch and my second is also 1/4 for a total of 1/2 inch seam allowance.
If I were using a pattern with a 5/8 inch seam allowance I would place my first stitching line at 3/8 and the second at 1/4 for a total of 5/8 inch seam allowance.
below I am using a straight stitch foot, a 1/4 quilting foot works great for French seaming too.
Step 1. Place fabrics WRONG sides together and sew using a 1/4 seam allowance
Step 2. Trim seam allowance to about 1/8 inch, careful not to trim too close to stitching
Step 3. Press the seam to set the stitches
Step 4. Press Fabric RIGHT sides together at the seam (your raw edge is now inside your fold)
Step 5. Sew another seam, using a 1/4 seam allowance along the folded edge.
(this seam encases the raw edges you sewed earlier)
Step 6. After pressing the seam to set the stitches
press your fabrics open
Step 7. Press the French seam to one side (usually the back)
and you are done with this seam!
See how nice it looks in a finished garment?
can you even see it? look close!
Ta Da! No raw seams!
Thanks for help with the pictures Slick! :o)