Since I came across Elizabeth Zimmerman's sewn bind-off in her Knitter's Almanac, it's been my go-to method for circular items. Mainly because it's so simple to do, but gives maximum flexibility as to how tight or stretchy you want to make it. While photographing the final part of the "Demystifying Toe-up Socks series", I took the opportunity to take some pictures of this too - I hope you'll find it useful.
Step 1: Cut your yarn, leaving at least three times the length of the edge you're casting off and thread the end through a (sewing) needle. Insert the needle through the first two stitches, working from right to left, then pull the yarn through, but not too tight.
Step 2: Thread the needle back through the first stitch, from left to right. When all the yarn is through the stitch, slip it off the knitting needle. That stitch is now bound off.
Step 3: Repeat steps 1 and 2, ensuing to keep the stitches even and with the desired tension - too tight and you won't get much stretch. Too loose and it won't look very neat!
Step 4: When there is only one stitch left, sew into the first stitch that you bound off. Then sew-in the ends.
The final part of the sock series will be published on Thursday, when we'll be adding the afterthought heel to our sock. In the meantime you can find lots of other tutorials here.