> Look at an audio file's waveform before playing it at max volume.

This is important, but more broadly, practice good sound hygiene: wear headphones them around your neck until you know for a fact that it's safe to put them on your ears. Additionally, never play "new" sounds without remembering to set audio output to a tiny fraction of normal and increasing it after the sample is deemed safe.

Musicians have this drilled into them because it involves their daily work, but this is good advice for everyone. Damage to ear drums can be permanent.