For this hat I cast on 87 stitches and worked a two x two rib (knit 2, purl 2) until I felt the hat was a decent enough length to fit my head. Then I began decreasing every other row for 14 rows. My decreases were as follows:

knit/purl in pattern and p2tog every 13 stitches;
knit/purl in pattern
knit/purl in pattern and p2tog every 12 stitches;
knit/purl in pattern
knit/purl in pattern and p2tog every 11 stitches;
and so on until I got down to about 39 stitches left on the needles and began k2tog or p2tog depending on how the stitches that were left looked.

I didn’t make a note of how many stitches I had left on the needles when I gathered what was left together and closed up the top of the hat. Then I just wove in the ends.