Originally Posted by salmonmac
The yarn over is done a little differently after a purl stitch or between two purl sts but the outcome as Antares described it, is an extra loop over the needle before working the next stitch on the left needle.
Yeah, everybody always says this, but I can't tell that's there's any difference in how you do a YO before or after any stitch. It's still wrapping the yarn once around the needle no matter what stitch it comes before or after. Now where you position
the yarn to make the next stitch might matter, but even then, that location is no different from where you'd position the yarn to do that particular stitch anyway.
This really really REALLY confused me when I first started knitting, and when I finally figured it out (thanks to suzeeq), I thought, "Now why the heck did everyone have to confuse me about this? It's not difficult, and yet everyone's making out like it is!!"
So here's suzeeq's advice (since she's no longer here): For a YO, wrap the yarn around the needle in the same way you would wrap it to a regular knit stitch (or purl stitch--it's wrapped the same way for both stitches, so either will do). Then bring your yarn to the correct position (front or back of needle) to do the next stitch! Easy-peasy and a lot less confusing!