Walking into a commercial gym for the first time can be intimidating, partly because there's a set of unwritten social rules that experienced gym-goers observe instinctively. Violating these norms creates friction and makes the gym a less welcoming environment. Understanding them from day one helps you integrate seamlessly into the gym community.
The fundamental rules: always rerack your weights after use - leaving dumbbells or plates scattered around is inconsiderate and potentially dangerous. Wipe down equipment after use, especially benches and handles where contact is extensive. Don't talk to someone who's mid-set - wait until they've completed their set and replaced the bar before initiating conversation. Respect personal space; hovering near someone waiting for their equipment creates pressure and ruins their training focus. Offer to work in on equipment if you'll be waiting more than one set.
Phone use: keep calls outside the gym floor. Music through earphones is fine. Taking videos of yourself is acceptable but don't film others without permission. Regarding mirrors: they're for checking form, not exclusively for selfies. Share benches and equipment during peak hours by alternating sets. Limit equipment occupation to what you're actively using - don't claim three pieces of equipment simultaneously during busy periods. These simple courtesies cost nothing and make the gym a better environment for the entire community.