Situational awareness: "It struck without warning" is rarely true. If you WANT storm warnings you can GET storm warnings. Don't depend on hearing sirens inside your house. A weather radio is best, a local TV station is good too. LOCAL, not CNN or Discovery.
A tornado watch means conditions are right for tornadoes to develop. A tornado warning means radar has indicated a tornado is imminent and/or someone has actually seen a tornado.
Radar does not show what's happening on the ground. That's where trained spotters come in. DON'T go looking for storms without training. You can be hurt or killed.
The "bent neck" rule: If you're bending your neck to look up at a funnel, YOU ARE TOO CLOSE!
Don't take cover under an overpass because it turns into a wind tunnel. A TV crew got away with it once. Others have died.
There are a lot of scary looking clouds. There are not that many tornadoes.
And it's not just about tornadoes. Flooding and lightning are the top two storm related killers.
Don't drive into water if you can't see the road under it. The water is deeper than you think. Turn around, don't drown.
Even if you're not close to the storm, if you can hear thunder you are close enough to be struck by lightning.
Know what's happening around you and know what you will do if something happens. Planning avoids panic.