I like Elizabeth Zimmerman's ways of using short rows on collars. It can be used either bottom up or top down. I've used her method to add rows around a collar to make it higher, and to make the back of a sweater longer. So far in knitting sweaters, I've found her methods (the percentage system) to be the least stressful and successful as well. All the sweaters have fit, which is more than I can say for some patterns I've knit up.