We start with our old friend, the slip knot. Situation normal, right? But this time, we're using waste yarn, in a contrasting color to the yarn we plan to use.
Place the slip knot onto the crochet needle.
Crochet needle in right hand, knitting needle in left hand. It's like a crafting yin and yang.
Hold the yarn in your left hand (along with your knitting needle) and make sure the yarn is running under the knitting needle to the crochet needle. Hook the yarn with your crochet needle, pulling it over the knitting needle:
Then continue pulling it through the loop on the crochet needle:
Tighten down the stitch by pulling on the yarn your left hand:
Voila! One stitch cast-on.
Repeat, starting with the step that begins "Hold the yarn in your left hand.." until you've cast-on the desired number of stitches.
Here's what it looks like after you've cast-on a few (not to be confused with tying on a few):
Now you can go ahead and use this as your cast-on, but I didn't do all of that work (crocheting is flipping hard, apparently) for a crappy edge.
Tomorrow: How are we going to use this to facilitate a super awesome cast-on?