going to gym for the first time

Hey everyone, I’m about to start going to the gym for the first time and wanted to ask for some advice. I’m a complete beginner, so I’d really appreciate any tips on things I should keep in mind: whether it’s about workouts, form, diet, gym etiquette, or even mistakes to avoid.

What do you wish you knew before you started? Any beginner-friendly routines or habits would also help a lot. Thanks in advance!