Working from RS, PU 1 stitch by putting tip of right needle between edge and next stitch, wrapping yarn as to knit to make stitch on first needle, then YO second needle, keeping PU and YO snug to needle.
This technique is also knows as PU1/YO.
In Jill Wolcott Knits® patterns, I often use the term “pull up” in place of “pick up” as I think the term is clearer, because you’re pulling up the thread to work it.
Taming Techniques Episode 103 – Pick Up Yarn Over from Jill Wolcott on Vimeo.
Taming Techniques Episode 103 – Pick Up Yarn Over from Jill Wolcott on YouTube.
See also: yarn over, double yarn over