Anyone have a good recipe or tips for making sauce from fresh tomatoes?

I have a bunch of Roma's and cooked some down for sauce. About a pint, just enough to try for spaghetti.

I blanched 'em then peeled and cored, but didn't pull out the seeds and juice. Then mashed and cooked 'em down.

Added garlic, basil, onion powder, black pepper and salt.

Flavor was OK, but it was really watery.

Do I need to remove the seeds and juice? Or just cook down longer?

Thanks! Virgil B.