Variety makes a huge difference as well. We make a variant of Caprese salad frequently, which is something that depends heavily on the quality of the tomatoes, and we basically have two choices when making it for optimal flavor:
- Use tomatoes we grow ourselves (we live in the northern US, so that's possible for about 2 months out of the year)
- Use Campari tomatoes, which we are able to get hydroponically grown relatively nearby and packed ripe.
Camparis are a highly flavorful variety, one of the most flavorful that are easy to obtain (at least in our area), and because we're able to find a source that gives us fully ripe tomatoes consistently, they turn out very well. We've tried with quite a few other varieties and sources, and even in season haven't gotten results near what we can get out of season with hydroponic Camparis.
You may want to find out what varieties of tomatoes are commonly used in the dishes you prepare - depending on what kind of flavor you're going for, plum, campari, or roma may be a good choice, for example. This site recommends Plum tomatoes for sauces, for example.
I also see the desi tamatar, which seems to be a common Indian variety of tomato, which seems very similar to the Campari, both in appearance and flavor; I've seen some recipes that consider the two identical, though I suspect that's not truly the case (as the Campari is a recent hybrid developed in Europe).