If you don’t already have a chimney cap (spark trapper/ wildlife baffler/rain roof) get one. Your chimney sweep can sell you one, and good luck will rub off, etc. Critters, from birds to raccoons, want to nest in your chimney, and it won’t be a good chimney when they do.
It’s easy to forget to close the flue the day after a fire. Plow and Hearth even sells cutesy brass doodads to remind you the flue is closed. Heating $ go up the chimney when the flue is open.
If your house has air conditioning, sometimes smoky-smelling air will come in, even with a closed flue. I know of no cure.
If you have seen Mary Poppins, some fireplace activities will bring Dick Van Dyke to mind. I know of no cure.
Fire has an effect on people. They quiet down and watch the fire. They also want to tinker with the fire. Because of that, a fireproof hearth rug is a good idea.
A bellows is a good fireplace accessory.
Candle stubs help to start a fire, but some will disagree with that .