Roll twice to put out the flames. Remember that rolling uses stamina, so keep some saved up!
You don't have to stop, but definitely drop and roll.
Stop the Bleed
So you've been shot with a nail gun. It happens. However, nails cause bleed damage (similar to fire). To stop bleeding, stand still for a few moments. Running will make it worse.
Don't Gib Yourself
Certain weapons and throwables can damage you if you're too close. If you gib yourself, you will lose points.
Watch out for:
Explosives (RPGs, Grenades)
Molotov Cocktails (will need to roll out fire)
Poisonous Gas
Equal and opposite reaction, yada yada yada.
Find the Leader
The player in the lead (most points) will have a floating, glowing crown over their head. Successful attacks on the leader grant bonus points.