You might still be accidentally bringing the yarn over the the needle when you switch from knit to purl or purl to knit. Also check at the beginning of the row - if you have the yarn to the back over the left needle it can pull up the first stitch so its legs look like 2 sts. Or you could be wrapping the yarn around the other end of the needle when you begin a row. Hold the yarn off the side a little bit so you can see the first stitch clearly and get the yarn in the right position to work it.
sue- knitting heretic