Realize that depression is a temporary thing, and don't focus on it as the central theme of life. Weeping may endure for a night, but joy cometh in the morning. Pray about it. Never doubt that God already knows what is in your heart and will not be shocked when you speak it to Him in prayer. Cast thy burden upon the Lord, and He shall sustain thee.
Depression preys on idle time.
When your hands and mind are full of the work at hand, there's little time to focus on depression. If work and family don't fill your time, give some of that spare time to volunteering where you are needed. It will help others and help you fight depression. Talk to somebody. When King David was cast down over the loss of his best friend Jonathan and Jonathan's father Saul, he found release in talking about their lives and actions.