I use the Florida Weave to keep my tomatoes propped up off the ground, so the first thing I do before planting is get everything setup to receive the tomatoes. I space my tomatoes two feet apart with supports essentially every four feet putting two tomatoes between supports with about a foot between the nearest tomato plants and the support. To help keep everything marked I push little pieces of wood where the tomatoes will go. There won't be any stringing for a while yet, but since driving the 8 foot tall stakes into the ground is a production I do it well in advance so as not to disturb the root systems of the tomatoes.
I then go around and dig out the hole for all of the tomatoes at the same time. Last year I didn't do this and had issues with excavating holes next to planted tomatoes. This also let me sprinkle some Tomato Tone fertilizer over the whole bed once the holes were dug. The theory being that when I fill the holes back in there should be a fairly even distribution of fertilizer at all depths. I like to bury my tomato plants so that only the top one or two branches are above ground. The stem should produce roots along the length that is buried for extra nutrient absorbing power! I place the tomato in the hole to make sure the depth is correct and either remove or add soil to adjust the height.
Once the height it correct I then remove the leaves from the lower branches leaving just the branches. These two can potentially put out additional roots. I label all of my pots with the variety of tomato in them. At this point I write the variety name onto the side of the stake closest to the plant. I use a sharpie and this helps me keep which plants are which straight.
After that step is done I fill in the hole with soil and water liberally. If you have mulch available to prevent soil splash onto the leaves then now would be a good time to apply it. After I planted my tomatoes I planted carrots and beans around them to provide ground cover when they come up, so smothering them with mulch was out of the question. I also plant basil among the tomato plants for easy access to basil + tomato when I'm munching in the garden and because the basil discourages some tomato pests from hanging around.