Fire
The next point I will touch on moves from cold back to hot, i.e. fire. This wonderful tool is like any other, it will turn and bite you if you mishandle it. The fire safety consultant would like to mandate a minimum of 10 feet between open flames and tents. I wish them luck since common sense is hardly common. (For instance, what is an open flame is a question that they have a much more restrictive answer to than is normal.) The rule of thumb I use is "far enough away so that the fire cannot be knocked into the tent." Except in extreme drought years (2 so far), the grass is wet enough that flames will not spread quickly. If there is a drought, special rules are published to reflect the pertinent dangers.
Never have an open flame in a tent. Most modern tents are too air tight and are made with fabrics that melt too fast and too hot for you to want to take chances. Even Fire-retardant canvas will burn if heated long enough. Most Pennsic campers set up their tents with at least 3 feet between tent walls, in the hopes that if there is a fire, it will keep it from spreading. If this seems like a lot, look at the guy lines from a properly set 3-person A-frame pup tent and you will find that two of them end up having their walls three to four feet apart.
This was brought home at Pennsic 25 when a candle in a tent fell over and, after a while, set the canvas on fire. I understand it was spectacular; the pictures sure were. Quick thinking by the security team that spotted it probably saved the lives of the folks in the tent. The space between the tents and further quick response by folks with extinguishers saved the surrounding tents. It was stiff competition for horrifying sights for the Pennsic 23 "brazier heating a dome tent" meltdown / implosion / fire (pick one, they all kind of fit).
As for campfires, if you are not good friends with Prometheus, be very careful. Let me put it in simple terms. Amateurs make me nervous, and a wood fire can be a hard teacher. There are very few people in the world (let alone at Pennsic) who are good at treating amateur fire gods who become burn victims. There are enough accidents, do not go looking for trouble. If you are not used to fires, learn by observing and take your time.