There are few things worse than having to get up in the middle of the night to check on a fireplace, or having to restart a fire in the morning after it has gone out. Leaving a fire fully burning over night can be dangerous. Banking a fire allows the coals to stay hot all night, making restarting the fire a breeze the next morning.
Accumulate a pile of ashes while burning wood in your fireplace. This is easier if you have already used the fireplace a few times and have ashes available from the previous fires.
Wait for the fire to start to die down. It is much harder to bank a fire when it is new. You need the hot coals that you can only get after the fire has been burning a while. Don't put in any new wood.
Using a fireplace shovel, push all of the coals and still burning logs as close together as you can. This will help to retain the heat and keep the fire going. As you push the logs around, scoop cold ashes to the outer walls of the fire.
Pile the ashes in an even mound around the burning coals. Build it up along the sides of the fire first, and then scoop the ashes carefully on top of the coals. Don't pile them too thickly, and don't pack them down. Some air still needs to be able to reach the fire. Without enough air, the fire will die out completely.
Put the screen for the fireplace back in its proper location. This will help to prevent a house fire, just in case the coals do rekindle and start a fire. This will also help to keep any scraps of paper or other flammable objects away from the fireplace while you sleep.
To restart the fire in the morning, carefully knock the shovel against the coals and logs to remove the ashes. You may need to blow gently on the coals to get a fire going; a small amount of newspaper or some loose kindling can help. Once the fire is going, add in more wood. It should catch fire within a short amount of time.