I completely forgot how to do blanket stitch the other day and had to look it up! Just enough to get myself back on track, but even so, in case it happens again, I've written and photographed myself a reminder. Here's how I do it....
When using blanket stitch I always work from front to back and right to left, you could always swap this around once you have the hang of it if it's more comfortable.
Begin by taking the yarn through from front to back.
Repeat, so you have a stitch looped over the work (Martha calls this an "earring", which I love).
Take the yarn through the loop from left to right, and pull tight (not too tight, just so the stitches sit nicely on the work without cutting into it).
Working away from your first stitch, take the yarn through the work from front to back again, leaving a loop.
Bring the yarn through the loop from left to right...
... and pull tight.
Continue working evenly along, repeating stitches as above.
So satisfying, simple and a lovely way to edge pretty much anything.