Hrmm. I make a lot of hats. But is that a bad thing? Here's a pattern for one I made recently.
I used caron simply soft in lime green and purple. (I don't remember the exact colorway) and I used size US 5, and 8 needles. And of course, the stripes are optional.
Sadly, my pictures are HTM files and I can't upload them and I don't know how to change them to a JPEG.
Cast on 70 stitches with size 5 needles, place end of round marker, and work 1x1 (k2 p2) rib for 12 rounds (you can do any amount, but this is how many I worked)
Switch to larger needles, and work increase as follows.
Increase: *k2, m1, k2, m1, k3, m1* Continue * to * all around.
Body of hat: I just knit in stockinette stitch all the rest of the way for about 7 inches. I made 5 stripes, each one I worked 5 rounds.
Decrease rounds 1 - 3: k2tog all around.
Break yarn, thread onto yarn needle, and pull through remaining stitches. Enjoy your new hat!