To tell you the truth, most people do not know what to do about depressed people. Depression is an area of feeling that people just feel uncomfortable around. It acts like a blocker in communication, not just in them giving a message, but in the other person receiving a message. Attitude really affects how you think of things.
I found there were a couple things that really helped me. One. Know what you are trusting in and reflect on that. I believe the Bible, so I will share some things from there. I believe that all people are sinners, and that God is holy and cannot be around sin, and so we are separated forever from him in hell and the lake of fire. Romans 3:23, "For all have sinned, and come short of the glory of God." Habakkuk 1:13, "Thou art of purer eyes than to behold evil, and canst not look on iniquity:" Psalm 9:17, "The wicked shall be turned into hell, and all the nations that forget God." I also believe that God does not want people to go there, and he made the way to have your sins removed from your account, and that it cost Him his life, but HE DIDN'T STAY DEAD. John 3:16, "For God so loved the world, that he gave his only begotten Son, that whosoever believeth in him should not perish, but have everlasting life." John 10:30, "I and my Father are one."
1 Corinthians 15:3,4, "how that Christ died for our sins according to the scriptures; And that he was buried, and that he rose again the third day according to the scriptures:" Importantly, I believe that this free offer comes with a time limit. John 6:44, "No man can come to me, except the Father which hath sent me draw him: and I will raise him up at the last day." Proverbs 28:13, "He that covereth his sins shall not prosper: but whoso confesseth and forsaketh them shall have mercy." And you can't work for it. Ephesians 2:9, "Not of works, lest any man should boast." Summary of first point: KNow what you believe.
Second point, and this is going to sound cheesy, but think positive. It really helps. Avoid music that has negative messages, whether by tone or words, and nothing loud. Wear any color but black, even if you like it. And avoid colours you hate. For me that colour is pink. So I avoid that colour. Concentrate on positive things, like true, right, good. (Philippians 4:8, "Finally, brethren, whatsoever things are true, whatsoever things are honest, whatsoever things are just, whatsoever things are pure, whatsoever things are lovely, whatsoever things are of good report; if there be any virtue, and if there be any praise, think on these things.)