Tomato plants sprawling on the ground are more prone to diseases; fruits touching the soil often start to rot. When many of the fruits develop, stalks can snap under all that weight. To grow healthier plants producing more crops, you should provide some kind of a support. Stakes, cages, or trellis can do the job well enough. However, staking seems most convenient.
Why? It allows you to plant tomatoes closer to each other, than you would be able to, when using cages. Moreover, cages are often too small and poorly made; they break after a while. You can easily access staked plants to perform any gardening procedures.
Collecting fruits is simpler, when they lurk just under your nose, instead of hiding behind the bars. Finally, stakes take much less space in the shed, when stored for winter. Trellises provide a good reach, but they can be a fragile support for determinate tomatoes.
Choose some sturdy stakes, 6-8 feet long. Wooden or metal ones will be ok. Set them up as soon, as you plant the seedlings. If you stake too late, the poles may injure some of the roots.
Push 1-2 feet of an each stake into the ground, 3'' from the base of the tomato. Make sure it will be stable during a bad weather. As plant can't attach itself to the stake, you must tie it to the pole. Use cotton strips, because they never cut into the stem, injuring your vegetables.
First, knot the strip to the stake so that it doesn't slip down. Then, loosely attach the seedling. As the plant grows, add a new strips every 15'' or so.
For indeterminate variety, remove all the suckers (growing tips between leaf and main stem), but the two ones at the bottom. You don't want more than 3 vines growing from the one plant, because then the bush would be too difficult to stabilize.
When a tomato reaches the top of its stake, prune the top of a stem, so that all the energy and nutrients feed the developing fruits, instead of any new leaves. For determinate variety, remove enough suckers for the plant to stay close to the stake. It should not get too bushy.
That's all one should know about staking tomatoes. Get some natural bamboo stakes from Amazon to get started with stabilizing your crops.
Picture credit: Dwight Sipler, "Tomatoes on support", CC BY.