I've used the beautiful handpainted silk-merino yarn I bought from Hedgehogfibres on etsy last year to make a cowl for myself. I like the way garter stitch shows off hand painted yarn, but I didn't want garter stitch all over, so I've alternated between stockinette and garter stitch, which gave the added advantage of stretchiness. I wanted a cowl that would be quite snug around the neck, and long and wide enough to pull over my head. I also wanted it to flare a bit at the bottom, thinking it would sit nicely on the shoulders that way. I started at the top, deciding that a 60 cm circumference around the face would be good, so I simply cast on the number of stitches needed to fill a 60 cm circular needle, and didn't bother to count them, kept knitting for a while, increased a random number of stitches a random number of time, and cast off when I ran out of yarn. It' beautiful, but a bit short when I pull it over my head, so I blocked it, but then it lost its stretchiness. It's not snug like I wanted it around the neck, so I guess the jury' still out on this one.