Harry Klee, a researcher at the University of Florida published insights into improving tomato flavor in a 2012 article in Current Biology.
Klee believes good tomato flavor is a complex panorama of sugars, acids, and mysterious gassy chemicals that we experience as smell. Klee and his colleagues are still identifying those “aroma volatiles.” Reviewing 152 varieties of heirloom tomatoes, the researchers found more than 3,000 volatile chemicals that impact taste.
He recommends planting seedlings in rich soil with lots of organic matter, or compost. The interaction between the microbes can impact flavor significantly. NPR has an article, How to Grow the Tastiest Tomato? The Secret is in the Soil