I want to paint over my old brass coffee and end tables but I'm not sure how to go about it. Any suggestions or tips would be greatly appreciated.

I would clean the old brass with a laquer thinner then prime with an auto body primer then spray paint

not all paints are compatible with automobile paints or primers. there's an old saw in body shops, "anything can cover lacquer, but nothing covers enamel."

I don't see why a good clean brass surface isn't going to work with a standard spray primer and paint.