How do you knit up original designs? Do you do all the proper math and charting first, or just cast on and knit away?
I took the 'cast on and knit away' approach to a pair of mittens for my roommate, but am finding it has become a lot of trial and error, and I've taken them apart and restarted so many times. This is the first time I've ever attempted to knit something (other than scarves) without a pattern. Am I approaching this wrong?