I recently learned the Berry Stitch and made a long round scarf. It was too long so I unraveled it and used the yarn to make this brown beanie with the same stitch. I absolutely LOVE this stitch! I think it's perfect for beanies because it allows the finished piece to stretch. The beanie fits me, my husband, even our 2 year old son very nicely. I like it for the one-size-fits-most effect.
I personally like to wear the Slouchy Berets or Tams so I made this Purple Tam to go with a shirt that I have. I really like how it fits and, again, the stitch allows the hat to stretch and breath. This picture isn't showing the true color; the hat is actually a dark purple.
I liked the hat so much that I had to make it in a teal color. I may just make them in all colors. Lol.
I also really like this stitch because it makes the stiffer acrylic yarn feel much softer and less stiff. It's great you just have to try it!
Insert hook into next (or specified) stitch, pull up a loop. Now you should have 2 loops on the hook.
YO, pull through 1 loop, Repeat 3 times
YO, pull through both loops on hook.
On my berry stitch I only repeated the 2nd line 2 times instead of 3. I'm sure you can moderate it as you like to get your desired look & texture. =)
Have fun being creative.