I find that most problems with good mitre corners is the seam width doesn't remain constantly to the place where you stop. The feeddogs tend to pull the quilt about the last 1/2" or so making the seam narrower. There is an interesting video, I believe, at the McCalls web site where Patrick Loose shows a place at the corner where he trims. I don't have the site but you might be able to search his name. It may be Lose. With a binding cut at 2.5" I use a 3/8" seam. It tends to fold over better. I use a lot of borders on my quilts so I can do more than 1/4" seam.

Most times I can make perfect mitered corners. Being careful is very important. I have tried the cutting off of the corners and it did not work for me. I have better results if I run off at a 45 degree angle at the corners. I now only machine sew my bindings on.

If you use 3/8 seam do you stitch to 3/8 from end when making your turn instead o 1/4 inch?

Yes.

If using 1/2 inch seam, one would stop 1/2 inch from the end.

I get really annoyed at all the binding instructions that say to stop stitching 1/4 inch from the end. That ONLY works if one is stitching a 1/4 inch seam.

The distance to stop from the end - is the width of the seam allowance for that first stitching.

As Peckish and others have said -

We have better results when we ONLY fold our bindings in half - we do NOT press them in half - that pressed line is NOT helpful when it comes to the turns - because the pressed in fold line is not where the fabric wants to go naturally.

The outer layer of the binding has to go a longer distance than the inner layer of the binding. Every time the binding is turned, the "fold line" is moved over a little bit.

I also baste the raw edges of my bindings together before applying them. It eliminates shifting of the binding edges - especially when using bias binding -so it turns over smoothly.

Patrick Loose or Lose, not sure of the spelling, has a great tutorial on binding.. So does Jenny Doan on Missouri Star Quilt Co.. I would not snip the corners, if the binding is folded correctly you will have some bulk but not too much..

This is what I do on all my quilts now and I like the results this gives.

Watch Patrick's video. It is the little triangle folded in the mitre fabric that he cuts. It reduces the bulk yet leaves the corner layers intact.