Know your rules. Keep the muzzle downrange at all times. Carry pistols in your holster or in their case if you have one. Carry rifles in a bag or cart, or if you don't have either, carry it with the muzzle up and the magazine removed.
When not firing stay well behind the bench and other shooters. At my range you can step forward to load any external magazines if you're the next shooter. With an internal magazine like a bolt action rifle or shotgun I typically don't load until I'm up to shoot. With the magazines, you can fill them but don't load them in the gun until ready to fire.
Keep your finger off the trigger until you've picked a target and are ready to fire at it. Keep the muzzle downrange at all times.
If you're sharing a bench with other shooters (you often will) you'll have to clear how you're going to go out to check the targets. You'll want to go check your shots but everybody should have their magazines and weapons cleared when people go out to check their targets. Nobody should have a gun in their hands (although I sometimes load magazines) when somebody's on the range checking their target.
This is obviously on a range with self regulated lanes and no ceasefire. Learn the individual range rules and follow them to a T. Also, and this is a big one, find out what's allowed (steel ammo, rimfire, rifle size, etc.). Know where you're supposed to be. We have pistol bays and larger bays. However, they allow .22's and sometimes carbines or shotguns in the pistol bays. A pistol can be shot in any as far as I know but if you don't have a rifle you shouldn't use a rifle bay in case somebody with one would need it.
If you want to approach somebody, wait until they don't have a weapon in their hands and I like to tap them on their shoulder to get their attention. This is how I get the attention of my family members. I've also done it to ask weapons of the instructors shooting and once to complement a man on his 1940's era Thomspon (fully automatic and very fun to watch).
Keep the muzzle downrange at all times.