Today I worked on a scrappy project... doing the binding on it. The corners of this one aren't 90 degrees and as I was doing them I thought that maybe someone out there would like a tutorial on how to do binding. If you follow this step by step you'll be able to do 90 degree bindings and odd ones too.
I cut my bindings about 1-1/2" to 2" for most projects since I do single layer bindings... in other words, I turn my bindings to the back, turn under the raw edges then stitch them down. Many people do double bindings... they stitch the fabric on double (it's folded in half lengthwise, both raw edges being caught as they go around), then when they turn it to the back, it's already folded on the edge. If you do double bindings, you'll probably be cutting them 2-1/2" or so.
Another choice in binding is cutting it straight along the WOF (width of fabric) or cutting it bias (at a 45 degree angle to the selvage). On this project I cut it straight but I usually prefer bias binding. Either way will work with the tutorial.
Here's a link to it:
Let me know if you have any questions or if I can add pictures to make it clearer. I've helped my daughters to do bindings and I'm hoping that this will help others. Once you get the hang of it, it's pretty easy.