Mostly I shoot at outdoor unsupervised ranges.
If there is anyone else there when I arrive, I usually walk around and get an idea of what they are doing, maybe exchange a few words.
I'll wait till the other folks have gone down to check their targets before setting up mine.
Before firing (after checking no one is down range) I get some eye contact with the neighbors, maybe holler out "going hot!", maybe tap my ears if i see they don't have their muffs on.
After each string I usually look around to see if anyone looks like they want to go down range. If so, I safe the weapon, bench it, and pull back my hands with splayed fingers in an 'I ain't gonna touch that thing!' gesture. If there's only the two of us there, I may holler out "safe!". But if there is a third or more person, I don't want to be saying that the range is safe when I have no control over the third person's actions.
If you would have Liberty you must accept that individual security
is not the responsiblity of government. You must. - XAVIER ONASIS