I would go with the reference point idea. First as you make your turn to final, notice where your airplane is in relation to a distant object (ie a group of trees, a radio antenna) and see if you land on the far side. Then, next time, wait a second or two, and make your turn to final slightly past that reference point.

Keep an eye on your threshold as well. That is, most fields have a weedy area several hundred feet (depending on the size of your field) before the rumway, try to find some landmarks there too. And if there aren't any, laying an old tee shirt in the grass won't usually upset anyone.