Give them more, but not less, if you want results. If you don't have enough sun, stick to leafy vegetables and root crops. Or find a sunny space to share with another gardener. That means the plants are resistant to common diseases and nematodes that affect tomatoes and can ruin a crop at midsummer, just when the white bread with mayonnaise is ready and waiting for fat slices. To stretch the harvest, choose more than one variety.
Good soil produces the best plants, which bear the best crops.
Unless you did so earlier, put fertilizer or lime into the tomato patch just before planting. Tomatoes growing in pots are especially vulnerable to drying out. Look at them every day and check the moisture content of the soil. Mulch such as compost, leaves or grass clippings will help keep the soil evenly moist. The soil line should be just below the first pair of leaves, which will encourage roots along the buried portion of the stem.