Backstitch is my absolute favorite stitch. It's smaller, stronger, and easier to keep straight than a running stitch. It is the closest to machine sewing that you can get by hand - which is great for hand finishing seams that are too tiny to do on a machine! It's also a great stitch to use when embroidering - it creates clean lines and fantastic text!
It's also pretty simple.
So thread your needle and knot the end of the thread(s).
Bring the needle up through the back or wrong side of the fabric until you hit the knot. Take a small stitch to the right or left. When the needle goes back through the the wrong side, you'll be bringing it up through the fabric one stitch away from the last stitch. You will then push the needle through the fabric right next to the end of the first stitch.
Sound confusing? Take a look at the pictures. It will help!
When sewing, I tend to keep my back stitches nice and close, but they might have a little space between them. When embroidering, I tend to bring my needle to the front of the fabric and back down through the hole that I used to first pass the needle to the back to make them extremely close together. :)
For more stitches, check here:http://www.instructables.com/id/How-to-Sew./http://www.instructables.com/id/Embroidery-101/