In a few of my knitting patterns there are times where it is required to work a yarn over between a knit and purl or between a purl and knit. In order to keep the eyelet formed by the yarn over approximately the same size, you may wish to take extra care in these instances.
I have created a YouTube video that shows me working a yarn over between both a purl and knit as well as a knit and purl. You will also need to do some untwisting on the following row (also illustrated in the video).
Here's a short summary
YO between knit and purl stitch
The yarn is at the back of the work after your last knit stitch. Bring the yarn between the needles to the front of the work, and then wrap your yarn over the needle and to the back again, before bringing it back to the front. This makes sure it is wrapped all the way around the needle.
YO between purl and knit stitch
The yarn is at the front of the work after your last purl stitch. Bring your yarn between the needles to the back of the work, and then wrap your yarn over the needle to bring it to the front of the work, and then between the needles to bring it to the back again, where you will be ready to work your knit stitch.
On the next row/round
You will notice that the YO between the knit and purl stitches will be oriented correctly. The YO between the purl and knit stitches will be twisted. You will need to either untwist this stitch before working it, or just knit it through the back loop to adjust the orientation.