I start tomatoes inside from seed, I grow them under shop lights in my laundry room....keeping the top of the leaves as close as possible to the light without touching. That keeps them nice and stocky.
When it's time to plant (after all danger of frost is past), I sink the plant into the soil up to the last whorl of leaves. If stem is long, I dig a hole with a slanted side to ease the plant up without breaking it (see image.) The stem will grow roots where ever it is touching soil, more access to water. I keep all the stems going in the same direction so I know where NOT to stake.
I water the hole, then fill with soil, gently packing. I stick a label with the variety name in next the the base of the plant. I push most of it under ground so it will stay put through the summer.
I wheelbarrow stacks of newspapers out to the garden, and lay them about 5-6+ sheets thick all around the plant. I cover this with around 3-4" of bagged grass clippings, since it's usually early in the season, there aren't too many weed/grass seed in it. This will keep the paper in place, blocking weeds and keeping the moisture levels consistant. Normally, I don't ever water throughout the summer. Once or twice if it's a REALLY dry season. I'm not exactly sure of how, but I've heard that water stress (too much or too little) is one of the culprits in blossom-end rot, seems it affects the Ca/Mg uptake (?) Just like mulching trees, I don't put the mulch right up to the 'trunk'....I leave a bit of room.
My tomato cages are big. They're made from thick metal fencing material we use to keep the cattle in the fields. Many heirloom plants are indeterminate, they will keep growing taller as long as the season lasts. They are heavy, most storebought cages will collapse under this weight. I try to put the cages out within a day or two of planting or it can be difficult to fit them around the plant.
I put a stake (usually a tobacco stick, remember this is Kentucky) just inside the tomato cage, on the side facing the direction the wind usually comes from. I will usually 'tether' them out before they get big enough to catch the wind and topple over.
I leave about 40" between the larger plants, a bit less for the determinate plants (Romas, etc.) If I'm planting a lot of different varieties, I usually attach a label to the cage also so I can tell who's who easily.
That's it. The next thing I do is pick 'em. I do can them. I can describe that too if anyone is interested. You need a pressure canner though.....water bath processing isn't recommended anymore 'cuz the newer hybrids are lower acid and it's not safe at low pressure.