I gave up on the green yarn for now. It was seriously frustrating me. I'm not sure if it was the size 7 needles or the single ply yarn or both. Anyways, I got out size 9s and some random white yarn I had and started seed stitching again. It's coming out much better this time. You can actually see the pattern. I still have a hard time getting an even stitch in the first couple rows after casting on, but otherwise I think I'm doing pretty well for someone who has been knitting for less than a year.