If you've got a long row of tomatoes, the best way to stake them is to construct a wall out of T-posts and cattle panels. You can use a handy little device called a duratool to affix your tomato plants to the panel. The duratool is one of my favorite farm tools ever. If you've got a lot of tomatoes, this drastically reduces the time it takes to stake. The down side of cattle panel staking is that it's pricey, so I would only recommend this option if you've got more than 30 or so row feet of tomatoes planted. Otherwise, metal tomato cages or wooden stakes work well. Whichever way you plan to stake your tomatoes, make sure your stakes are in the ground before you put your plants in.
How far apart should you place your stakes? Many northern farmers swear by close tomato spacing for maximum production. I've seen recommendations as close as 18" spacing for tomato plants. If you grow below the Mason-Dixon, I find that this recommendation is a recipe for disaster. Southern climates are humid, and if you're in the Delta like I am, the soils are dense and full of clay. This is perfect breeding ground for blight and other fungal diseases. The best way to prevent the spread of those diseases is by spacing your tomato plants at least three feet apart, and make sure you have plenty of room for air flow between your tomato rows.
Okay, so we've got our stakes in to our beautifully double-dug soil. Now what? I know some growers swear by this, but I recommend against ripping stems off to plant tomatoes deeper in the soil. First of all, open wounds on the plants are entry points for disease. Secondly, those leaves are little solar panels, making energy for your plants to grow. I dig a hole 2-3 times the size of the tomato root ball, fill it with compost, then plant the tomato starts about an inch higher than the root ball's soil line.
Here in Memphis, my favorite tomato grower is Steve Fulwood of Cold Comfort Farm. He can grow beautiful, tender heirlooms long past the time my hybrids have succumbed to blight. His Brandywine tomatoes are my favorite. They're sweet, smooth, and the perfect slicing texture. My husband asked him last year what his secret was, and he shared his fertilizing plan. He saturates the soil under his tomato plants with Grow Big fertilizer from Fox Farm once a week until the plants start to bud, then he switches to Tiger Bloom. That plan has worked well for us, thought I have to admit... even with his fertilizer secret, I've still never been able to grow an heirloom tomato as perfect as his!