To begin, pick a place for your container that gets six or more hours of full sun.
Next, give them good soil. Tomatoes want it well drained and aerated. Add compost for nutrients, crushed eggshells for calcium, and top it off with some straw mulch. Be sure to plant them deep in the ground or container. Pinch off the bottom leaves and cover up to two-thirds of the stem so roots will shoot off helping the plant take up more water and food and keep them protected if the temps take a dip.
Tomatoes are a vine and need some support, so if you notice that they are looking a bit limp, stake 'em or cage 'em. Remember to water deeply and regularly and to feed your tomatoes too. Use a fertilizer labeled for tomatoes every few weeks.
Sun, soil, support, food and water, that's how you get a tomato to grow and that's good to know.