Knitting stitch tips needed for beginner.

[Fairlight65]

I am trying to knit a hat (a Calorimetry from knitty.com) I am having trouble knitting the knit 2 purl 2 to make the rib stitch. I keep messing up & before I know it I have knitted 4 and purled 2 or something then the rib stitch gets all messed up & I have to rip it all out.
I was wondering if