margecam52

I don't use a walking foot when binding (actually, rarely at all, find them cumbersome).
1. I don't press my binding in half. I do press the binding out flat (I use 2-1/2" wide strips cut on the straight of the grain...I only cut bias strips for scalloped edged quilts), pressing the 45 degree joins open.
2. I fold the starting end of the first piece of binding (before I've joined any strips together)..and match the cut ends...Put a pin in. I then pick my start point on the quilt (usually abt half way down one side. I pin the top (start) edge of the binding...using the pin I used when I folded it before. Then I pin, folding to keep the cut edges together, about 12" from that first pin (this is where I will start sewing on the binding. I sew onto the front of the quilt & fold to the back (but that's a matter of preferrence).
3. Sew to within 1/4" from the first corner (if you use a 1/2" seam allowance, sew to withing 1/2"...the rule is to stop the amount of your seam allowance from the corner). With the needle in the down position, raise the presser foot & pivot 45 degrees, put the foot down and sew off the exact corner of the quilt top. Cut the threads.
Now you are ready to fold the mitered corner, using the 45 degree stitching to the corner as your guide. You can't go wrong folding up to the stitchoff line. Once you have folded up on the sewn miter line, fold straight back down matching the cut edges of the binding to the cut edge of the top on the next side. Your goal is to have that top straight fold at a 90 degree angle, over the first fold. Now start your stitching at the very edge of the fold...to continue your stitching on of the binding down the next side.
Repeat for each corner.
Join the two ends as Leah Day showed in her video.

Leah Day looks to not pressing her binding in half either. Pressng the binding in half will make it hard to get a good binding turn when you go to turn the binding to the back. I always stitch down my bindings from the back. I use a color in the bobbin that matches the front background color...or if it's a busy quilt, I use .004 poly invisible thread in the bobbin. Usually though, a 60 wt bobbin thread (like bottom line thread) in as close a color as I can get works fine.
When I turn the binding to the back to start stitching...I can feel the edge of the binding on the front, and see the stitches on the back where I sewed down the binding on the front. I get my binding just a thread or so over that stitching and stitch down the back binding. You can hand stitch (I do when customer requests it, but also charge more for it).
If I were to press the bindng in half, I'd be struggling with that pressed in fold line...and my binding would not lay flat.