“Cheer up, asshole!”
No. That’s exactly the wrong thing to tell someone who is down. Never tell them to cheer up. It makes them feel worse, because when you’re down, you can’t just flip a switch and feel happy again.
I would just love someone I wanted to help feel better as much as I could. Mostly that means showing them that I understand as much as I can understand. I try to be honest about recognizing when I don’t understand. I don’t pretend to be able to do things I can’t. People often see this as lack of confidence, but that’s not how I see it. I think honesty is most important, because that’s what I want from others. I want to know the real deal.
So I would listen. Draw my friend out. Let them talk and talk, as much as they need to. I would sympathize, or at least make encouraging noises. I would hold them if they wanted to be held. I would pray with them (even though I don’t pray) or do whatever it was that they thought would help them, even if I didn’t think it was useful.
Perhaps the biggest thing, though, would be being there. Showing I care. When I was depressed, a lot of people disappeared and it confirmed my idea that I was a piece of shit with no friends. I would not disappear on a friend of mine who was in need of my comfort. No way!