Get a piece of paper out and draw up two columns. Label column one “# of Stitches” and column two “Decreases”.
Let’s say you have 60 stitches in your hat. Write that at the top… then write all the numbers that 60 can be divided by. 60 can be divided by 2, 3, 4, 5, 6, 10, 12, 15, 20, 30. Pick any of those numbers… for example let’s choose 10 and write that under the “# of Stitches” column. 10 goes into 60 six times, so write six in the “Decreases” column. So in the first decrease row, there will be six sections of ten stitches. In order to get those six decreases evenly across the row, you will need to do a k2tog in each section of 10 stitches. Subtract two from 10. 10 – 2 = 8. You end up with, k8, k2tog (started with 10 stitches, decreased 1 stitch down to 9 stitches). Working *k8, k2tog* the first row will decrease your hat 6 stitches. 60 – 6 = 54.
What next? Once you have your first row figured out, you just work down the line of numbers. So after the *k8, k2tog* row, the next decrease row would be *k7, k2tog* (9 stitches in each section, this still works because 9 goes into 54 six times!), then *k6, k2tog* (8 stitches), etc., all the way down to *k2tog*. Insert a row of k sts in between each decrease row to add a bit of length to the crown ( stop those types of rows when you get down to smaller numbers such as *k3, k2tog*).