From DIY Network Article
Install smoke and carbon monoxide alarms and keep them in working order.
Keep combustible materials like carpets, drapes and furniture away from the fireplace when a fire is burning. A guard in front of the fireplace will help keep children and pets from harm. Be sure there are no combustibles within 12 inches above the lintel (the metal plate at the top of the fireplace opening), including things like a wooden mantel.
Clean ash from the fireplace whenever it reaches the bottom of the grate, where it can impede airflow (an inch of ash in the fireplace will actually make it easier to maintain a fire). Wear a dust mask and gloves for safety.
Have your wood-burning fireplace and chimney cleaned and inspected by a certified sweep at least once a year, at the end of the burning season, or more often if you notice creosote and soot build-up over 1/8-inch on the inside of the chimney.
Test out the function of your fireplace by lighting a few small pieces of seasoned wood, lit from the top down. If smoke doesn’t exit vertically from the fireplace into the chimney, but enters the room, immediately troubleshoot and correct any problems. These can include creosote/soot build-up, other debris in the chimney like bird or animal nests, a damper that is closed or partially closed, or wet wood that isn’t burning well.
Burn only seasoned, not “green,” wood. Seasoned wood is wood that has been cut and dried under cover for at least 6-12 months, registering less than 20% moisture with a meter. Split wood dries more thoroughly and burns better than whole logs. Well-seasoned wood makes a sharp ringing sound when two logs are knocked together, while green wood makes a dull thud. Green wood will not burn as thoroughly, creating more soot and creosote.
Burn hardwoods, not soft woods. Hardwoods like oak, ash and maple are denser and heavier, delivering more heat than lighter softwoods like pine, poplar and cedar.