I don't. To me, telling a person with depression to ________(fill in the blank....sit in the sunshine, get out of bed, have lunch, etc.) is the equivalent of telling me to grow wings and fly.
I think what Pierro said is very valid. Accept that it's a bad day. Do what you need to get through it and then don't look back. Because getting through the day is sometimes a tremendous achievement in itself.
On the subject of telling people about depression, I will only tell those that have it....Those that don't simply do not understand. Just my opinion.
Keep it simple today. Tomorrow we will conquer !!