Don't EVER point the firearm at anyone, even if you KNOW it's unloaded. Always point it in the safest direction, generally either down the range or at the ground. Even if you are reloading or setting it down.
ALWAYS treat the firearm as if it's loaded.
Finger off the trigger until you are ready to fire. Your finger should never be on the trigger unless you are planning on pulling it.

Hopefully you are going with someone experienced who can show you the ropes. If not, ask the Range Safety Officer for some tips/pointers, they are normally happy to help.