>> My question is, did I put too many seeds together? They kinda spilled when I planted them.
Yup, everyone does that at least once, and some of us learn slowly, like me. I think it is easier to sow thinly or in individual cells, unless you are coordinated and tough-minded about yanking seedling around and letting any damaged ones die.
I agree with Elaine. And by the way, good photo. Worth 1,000 words.
>> You can't let all those babies grow in a clump like that.
Yup. They will turn into huge plants and strangle/starve/shade each other. Their roots would compete.
>> Take soft tweezers or your fingers very gently and see if you can pull out all but the strongest.
My method would be to FIRST slide a fork or two AROUND and somewhat UNDER each clump of seedlings, and lift the whole clump out of the flat as gently as possibly, trying to lift all roots whole.
Then spread the clump out on a flat surface and try to "tease" the roots apart while ripping as few roots as possible. But I'm clumsy and timid about seedling roots and stems.
I wouldn't even try to be gentle enough with tweezers to pull on a seedling stem - I would expect to squish it or rip it in half. With clumsy fingers, you might be better off gripping the LEAVES since the plant can ignore and replace a bruised leaf. Dented or bruised stems migh6 not recover or might be prone to damping off (rotted stem near the soil line).
Some people just say "Too bad so sad" and use small scissors to cut off (and kill) all but the best seedling in a clump. I have a neighbor like that and call her Attila the Gardener.
>> Then spread them around at least 3 or 4in. apart.
That's if you put them back into a communal pot or flat. Personally, I would transplant them right into separate cells or pots, like Dixie cups, Solo cups, or quart containers. That way, I would not have "prick them out" a second time. I hate doing that!
Some say that, when planting out into a raised bed, tomato plants should be 18 inches to 24 inches apart. I GUESS so, but my few tomato plants sprawled a LOT wider than 2 feet. Maybe they assumed that you would train the plants up onto a lattice or supporting twine (like Florida Weave).
And maybe have more than 2 feet between rows so you can walk down the row without burrowing through a tunnel of tomato boughs.