In the almost five years since writing this post I've discovered more ways to increase at the ending edge of Tunisian forward passes (often called the "left edge" by those crocheting right-handed). Below are links to videos for the method originally described in this post. You can also try the extended-stitch method in my free "Symmetrical Diamonds 101" pattern in Ravelry:http://www.ravelry.com/patterns/library/symmetrical-tunisian-diamond-101
My "Four Peaks Scarf" pattern explains how to use a type of Tunisian foundation slip stitch for this edge. Pattern in my DesigningVashti shop:http://www.shop.designingvashti.com/Four-Peaks-Scarf-Tunisian-Crochet-on-the-Bias-34-N31810TVG.htm
This video shows TWO kinds of half hitch stitches (one is the mirror image of the other). For the ending edge of a Tunisian forward pass, you only need to know one kind. You do that kind twice to result in the “double half hitch” (dhh).
So when you watch this video, you only need to learn the FIRST way they show how to add a loop to your hook. Just ignore the second way. Do the first way TWICE and you’ll have a dhh. http://www.anniesattic.com/crochet/content.html?content_id=87
This video shows one kind of half hitch (the only kind you need to know for the dhh) being put onto a knitting needle over and over. This is how I do it and I’ve really picked up speed making them by now. http://www.knittinghelp.com/videos/cast-on
Scroll past the first one called “Long-Tail Cast-On.” You want the second one, called “Single Cast-On Also Known As Backward-Loop Cast-On.”
(Thought I had posted the videos here, but I see that this 2009 post is much earlier than the later posts I wrote about this stitch for Tunisian edges.)