Many growers put up a stake every plant or two, however, for cost savings, I only place a stake at every 3 or 4 plants. Then I attach hay string between each stake along the row. The string is wrapped around each stake to provide maximum support. I run two or three lines along the row. One at about 12 inches above the soil surface and another 24-30 inches and so on as needed.
Once my string lines are up I attach tomato plants to the stake and string as needed to hold the plants up and off of the ground. I trim the lower 8-10 inches of branches off of each plant to encourage upward growth and to allow for easier weeding and to prevent transfer of pests and pathogens from soil to plant.