I forgot to mention something that works wonders for some people. You can buy some cheap orange cones. Walmart sells them for a couple bucks each. I take four and place two of them at each end of the field spaced out about 3 airplane lengths apart. I then practice approaches over the cones on both ends observing altitude and alignment until I can bring the plane straight down the center line between the cones each time.

You can practice this with a newby and it will teach them control on landing and help them nail down their approaches. Also, it gets ingrained and when you visit a new field you will "lock" on centerline quicker. For some this might not help, yet for most I have seen this has helped greatly.