Mary Corbet of Needlenthread has video tutorials on many different stitches. Here's how she tackles the tricky French knot. It's really worth practising this stitch - look at the beautiful flowers in this photo!
Simple embroidery stitch that starts with a row of simple back stitches. With a blunt needle, the yarn is then looped through the stitches. This can be done on fabric, of course, but is also beautiful on knitted or crocheted pieces.