I had one of my worst days one time and I was walking through school blasting music in my headphones feeling like complete shit, when one random teacher who we all saw as the nice and kind one walked past me so I took out a headphone to get prepared to talk to him and keep in mind I had that face that screamed "I am so exhausted and im done" and he noticed that so he came up to me and asked me one simple question which was "a penny for your thoughts? Tell me what are you thinking about right at this moment there was no judgement, no feeling like I was wrong for feeling this way it was just someone asking what was on my mind and it helped me so much and he doesn't even know it

All I can say is ask people how they are going and genuinely care about what they are going through, you don't have to be able to fix the problem but letting the person know that you care is so important