additionally, have fire alarms and change the batteries when they are low.
If you have gas heating, get yourself a good carbon monoxide detector as well!
I was going to buy one so I called my local fire station for advice and the advice they gave me was - make sure your fire alarms and smoke detectors are working, and if you have a fire, call 999 and evacuate.
I questioned if it wasn't better to have an extinguisher to try and get it under control, and he explained that most people have generally never used an extinguisher before (or would even know which to use for what fire), and even if they have, not in a real life panic inducing situation, and so are more likely to be wasting valuable time and putting themselves at risk, than actually put out the fire.
I'm sure this won't stop some people, but it was enough for me (he was right, I was calling for advice because I didn't have a clue, and for every person like me who asks, how many don't, and end up in situations like those I presume lead to him giving me that advice?).