This method is my favorite for double welt pockets, whether you plan on adding a flap or not. You will learn a relatively fail-proof technique for getting perfectly parallel welts with additional tips and tricks for sewing double welt pockets.
If you need help sewing the flap, which has a built-in turn of cloth, watch my video on the tailored patch pocket. The process is exactly the same:
• How to Sew a Lined Pat...
00:00 ---- Intro, Patterns, Fabrication
11:48 ---- Marking the pocket position
14:06 ---- Begin Construction, applying welts to project/sample
17:46 ---- Cutting the pocket opening
23:41 ---- Pressing the welts before turning
24:42 ---- Using a clapper for the pocket opening seam allowance
25:31 ---- Positioning the welts
28:20 ---- Basting the welts in place
29:09 ---- Stitching / securing the triangles
30:44 ---- Stitching / securing the top & bottom seam allowances
33:20 ---- Pocket Bag Lining
35:52 ---- Pocket Flap
37:50 ---- Pocket Bag Self