I've completed the stem stitch and back stitch on the tote bag project. The back stitch is very, very easy. Much easier to make it look smooth and pretty than stem stitch, which isn't exactly rocket science itself!
Wild Olive has some lovely pictures to illustrate back stitch on her blog here.
Here's the back stitch on my bag (it's the little red ovals):
Next up, a simple chain stitch for the yellow flower centers (you can see a little of it above), wash off the blue disappearing ink, and my tote will be ready for work/gym duty!