I didn't see this idea posted, but another thing you can do is take a scrap of yarn or dental floss and thread it through the stitches on the needle when you know the rows below are done properly. Move it up or add another as you go along (every 10-20 or whatever rows) so if you DO have to frog you don't have to all the way back. I use that method things like sweaters mostly now and I used it a LOT when I first started.
