Welt Pockets in 10 Steps:
1) Decide how wide you want the opening of your pocket. (The one pictured is 4 1/2" for cold, little toddler paws.) Mark the length and position on the right side of your pattern piece and back this area with fusible interfacing. The large rectangle marked around the pocket opening represents the interfaced area.
2) Cut welt and pocket pieces. (one welt and one pocket per welt pocket)
Cut a strip that is 1/2" longer on each end than the pocket opening (a little extra is fine, you can trim later before tucking in the raw ends) and twice the width that you want for the finished welt. Back this with fusible interfacing, fold it in half longways with wrong sides together and press (it's important that the long raw edges match perfectly).
This piece is shaped roughly like a kidney bean for this type of pocket placement but it would be a rectangle if you were adding welt pockets to the back of shorts or pants. The pocket needs to be 1/4" wider on each side than the pocket opening (the center crease pictured above is the area you need to measure, the length is up to you-deep pockets, shallow pockets, medium pockets, you choose!) Fold the pocket piece right sides together and press.
3) Match long raw edges of welt piece along pocket opening line. Pin in place. Lay pocket, right side down over the welt, matching pocket opening line and the pocket crease. Pin in place. (concave portion of the kidney bean/pocket pouch should be facing down)
4) Now use chalk or disappearing ink to mark stitching lines, 1/4" from the crease on each side and 1/4" from the pocket edges on each end. Stitch along marked line.
6) Press pocket to each side, creasing along seams (this will help when you turn the pocket to the inside).
6) Unfold. Inside the stitched rectangle, mark a straight line up the center and short diagonals from each corner. Carefully snip through all thicknesses along these lines, not cutting stitches.
7) Turn pocket and short raw pocket ends to the inside. With right sides together, match raw edges and sew pocket closed, sewing as close to the welt as possible without sewing through it. If the garment is unlined, finish pocket edges with zig-zag stitch or serger.
8) Now trim welt ends to 1/2" past pocket opening and tuck raw ends inside. I used the end of a writing pen to help do this.
9) Fold welt down and pin in place. Repeat on the other end.
10) Topstitch along each welt end. That's it! I did four of these babies in about half an hour, no sweat and very rewarding results! Use a heavy, duty needle for the topstitching!