Can you increase and decrease? If so, diagonal knitting will take care of pesky gauge issues.
Cast on 3 stitches. Increase in the first stitch every row, knitting every row, until potholder is width desired. At that point, begin to decrease on the first stitch every row until you have three stitches, then bind off.
Simpler than falling off a log!
You can make baby blankets using this method too, they are just bigger.
Important note: if using the yarn over increase method, you will have interesting holes where you increase, and they won't be on the decrease side. A better increase would be knitting into the front and back of the stitch.
And if you can't increase and decrease but now want to learn, Amy has AWESOME videos of different types. Thank you, Amy!