how do you cheer a sad person ?

[.kiki]

Peace be up on you all English club members.. how do you do? how's life with you guys

emmm, I needed help, and I didn't know where to go, so I decided to poste this topic here, maybe I get some answers..
so, guys, I have a friend who's passing through a difficult period, problems and headaches are a title to my friend's life now.. and when we're togethre, I feel I should cheer her up, maybe make her laugh or something.. just to wash away the sadness in her face.. I don't know how to do that! every time I see her so down and low, I become like her.. though I should make her feel that I'm there for her..
what would you tell a person in this situation ? I'm lost