I think a big hurdle to clear is learning how to stop negative thoughts as soon as they creep in, specifically the imagining of negative personal interactions or outcomes in personal and business situations. I think the more you dwell on negative possibilities, the more you create the negative outcome you imagined. I think there's a clinical term for it, but I can't remember. Basic stuff, but I think people fall prey to their own neurosis and realize their own fears/dread/doubts etc. But if you can train your mind to banish negative daydreaming, you are getting in front of the problem of depression and anxiety.