Self made Miracle Grow. Put 1 Tbs. Epsom Salt, & 1 Tbs. Sugar into each hole with your plant. It makes them grow larger, leafier and greener. Or dissolve 1 Tbs. Epsom Salt into 1 Gallon of water and use it to water your plants, trees, fruit trees, roses, flowering plants, squash,and all other veggies. For plants you have planted in ground or pots sprinkle Epsom Salt on top of the dirt/potting soil and water well. See Link for other ideas.
For more tomatoes - pinch off those suckers, the whole middle branch! Suckers are branches that grow in the middle of two established branches. They drain the energy and reduce the crop. Those branches in between can be removed, put in water to establish roots and then planted for a whole new crop.