One of the best methods for producing tomatoes is the string method.  Tie a lose knot at the base of your tomato plant and wrap the string underneath each leaf.  Once you reach the top of the plant secure the string above on a trellis or a rooftop.  The key is to maintain one shoot by removing suckers.  As the tomato grows higher, be sure to leave room to move the string horizontally to lower the plant height and continue vertical growth.  Over the summer, one plant can easily grow 10-20 feet long with up to 25 pounds of fruit.