Tomatoes need calcium to achieve their full flavor potential. When planting tomato plants crush up (to powder) about 4 or 5 egg shells and put them in the bottom of the hole. Then plant tomato on top. They'll provide calcium and prevent blossom end rot.
Did you know that your homegrown tomatoes will taste better simply by planting sweet basil next to them? This is just one example of companion planting with herbs. >Planting sweet basil in same pot with my tomato plants.