I went to the Seattle pops with some gardening friends on Sat and I never fail to learn something more. So here is a great hint we talked about.
You have tomato plants with lots of green tomatoes? Start removing any blossoms, and get all the extra small growth off the plant. This makes it easier for the plant to work on only the fruit that is there and unripened. So go pinch those blossoms and see if it works.