The next step in seed starting happens when the plants have their first two "true leaves." The first leaves, the cotyledons, were packed inside the seed and popped through the soil. These are plain leaves designed to store energy in the seed and then collect light to convert to energy to feed the growing plant. The next set of leaves are usually more ornate and look like the leaves of the adult plant.
When the true leaves show up it is time to "dibble" the plants out into more spacious pots.
Here we have a row of tomato plants on the left, and a couple of tomatoes already enjoying their new home. Tomatoes are very forgiving of root damage, but you have to take care to pick the plants up by the leaves, not the stems. I water the soil before I start working with it and I water again when I'm done, gently, to make sure there's no air around the roots.
I'm using old pots from years gone by. If I keep them out of the UV light as much as possible they will last four or five seasons. I never buy new pots, I just pick them out of other peoples' trash and wash them well.
My one flat of started seeds is now four-plus flats of seedlings. I'm swapping them out under the grow light and hoping for spring.