Whilst away this year I witnessed a very easy mistake. A family in another tent were cooking inside out. One tiny flame dropped to the ground and despite having a fire blanket ready, the tent burst into flames. It happened very, very quickly and within a minute the whole tent was gone.
Luckily there were fire extinguishers very close, plus other campers got ones from their cars as well. It was handled brilliantly and no one got hurt. It was extinguished before spreading to the next tent. However, very little of their gear was saved - a horrible end to a holiday.
Please don't let this happen to you.