as promised, here is a simple step by step for making the pocket bags on your shorts or pants french seamed. while simply finishing the edges with the serger or zig zag stitch is perfectly acceptable, the french seams make it so neat and tidy. so i see no reason not to do it this way!
fair warning: i did this about a month ago so if something i say sounds like gobbledygook... sorry!
the front pockets are the easiest so i'll start with that. here i have the pocket bag attached, under-stitched and pressed to the inside. now instead of folding the pocket bag to the side seam as the directions state, fold it under to line up the bottom edge with the wrong sides together and stitch the bottom of the pocket together at about 1/4".
trim the seam allowance by half. now turn the pocket bag so the raw edge is now inside the pocket bag and press the bottom edge.
stitch 1/4" from the edge encasing the raw edge in your stitching. baste the side of the pocket bag to the side seam allowance as per the pattern directions.
the back pocket is slightly more difficult to explain, but not hard at all to execute. if you're having trouble visualizing how this works (even with pictures) it's probably something that makes the most sense when you're actually doing it yourself.
so we start off after the welts have been sewn on and the pocket bag has been stitched to the bottom welt and everything has been slashed and turned to the inside. finish the side seams of the pocket bag, then press the pocket bag down.
now fold the pocket bag up to the waistband seam and put a pin to mark where the pocket bag edge was stitched onto the welt, as in the picture below.
now unfold the pocket bag and fold it under and line up the pin with the stitching line on the welt.
pin the lower half of the pocket bag at the side seams.
at this point the bottom of the pocket bag will be flipped up toward the waist. don't freak out, it's supposed to look that way.
now stitch the side seams at 1/4" stopping once you reach the point you originally marked with the pin.
now trim the raw edge down by half, stopping where you stopped sewing. see the pic below.
now reach in and pull the pocket bag down so the raw edge is to the inside.
press the seams and turn the upper edge of the pocket bag in as you press so it looks like the picture below.
stitch the side seams, encasing the raw edge, at 1/4" and continue stitching all the way to the top of the pocket bag.
make sure you grab the ends of the welts as you stitch up the sides.
now, admire your handiwork!