Another thing that might be happening: if you're switching from Knit to Purl within a row
make sure you always have the yarn in the back to knit
and in the front to purl
. Don't forget to put that yarn back where it goes each time...if you don't, you will add stitches...eeek!
And the most important thing of all...THIS HAPPENS TO EVERYONE in the beginning! I increased stitches for weeks before I knew people actually did it on purpose, LOL!