I know it's a bit long, but this video will show you how to use single fold as a trim, casing, facing, and how to turn a corner. I also share my own trick for how to evenly attach a bias strip that does not have the creases ironed in. (Skip to 9:30 for that part.)
Now that you know everything that I know about single fold. Here is a video for double fold. This one will cover 1 step and 2 step application, 3 methods for finishing corners, and also how to use it for facings. The down side? Oh yeah, it's even longer than the last one. Sorry! (I realized later that I didn't explain the mitered corner too well, so if you need extra help with that check out this tutorial. Scroll half way down to get to the mitered part.)
Information overload? Too bad,because I may even have a Part 3 for Monday. You need to know how to make binding for knits right, and it also might be helpful to know how to finish off the two ends if your working in a circle. We'll just have to see if I've got it in me this weekend. Maybe if I take a nap in preparation...
Thanks for visiting and have a great weekend!