Tutorial: Flat Felled Seam
1. Place your fabric wrong sides together – I know what your thinking, and yes totally opposite to a standard seam.
2. Sew your seam allowance, standard is 5/8 but double check your allowance.
3. Press open and trim one side of the seam to 1/8 and neatly fold the other side’s raw edges inwards by 1/4, press and fold inwards again. You should have no raw edges showing, just a neat channel running through your fabric.
5. Finally top stitch close to the seam fold and you should be left with a neat looking seam.